Working to make government more effective


How are bills amended by Parliament?

Amendments are proposals to change, remove or add to the existing wording of bills to modify their effect.

What are amendments to bills?

Amendments are proposals to change, remove or add to the existing wording of bills (draft legislation) to modify their effect. Parliament’s ability to propose such changes is an important part of the legislative scrutiny process.

Different processes apply to amendments to motions. Motions are statements that outline a topic for Parliament to discuss or a question for it to decide. They help to structure parliamentary debate.

Who can make amendments?

In most cases, bills can be amended by both the Commons and the Lords. However, there is no Lords committee stage for ‘bills of aids and supplies’” which authorise taxation (such as finance bills) or ‘appropriation bills’ which authorise government spending – the Lords cannot therefore amend such bills.

Amendments may be tabled by any MP or Peer.

Why are amendments proposed?

Most amendments agreed to are proposed by the Government. They may be proposed for several reasons:

  • To ensure the bill functions as intended: government amendments may reflect concerns that a bill fails to achieve its stated policy aims or has unforeseen or undesirable side-effects. Minor changes to the wording or ordering of a bill are usually uncontroversial, and not usually subject to debate.
  • As concessions to those who have raised concerns: government amendments may also address concerns raised during debate. These will often be compromise amendments, going some way to address the concerns voiced by opponents, while protecting the original aims of the bill. Occasionally, the Government will achieve the same effect by supporting amendments tabled by backbenchers.
  • To fill out the bill: it is not uncommon for governments to make amendments to fill out the bill as underlying policy evolves. For example, in 2019 the Government added Knife Crime Prevention Orders to the Offensive Weapons Bill.

Although amendments must be passed in order to ‘stand part’ of a bill— in other words, to be incorporated into the legislation and have legal effect—even amendments that do not pass can still have political effects. This is often the case with non-government amendments, which can sometimes be proposed for other reasons: 

  • To make a political point: MPs or Peers, particularly those from opposition parties, may propose amendments with the aim of advertising alternative policies or challenging the Government. These will often have little chance of succeeding but are a means of debating concerns in Parliament.
  • To probe the Government’s reasoning: some amendments are tabled to encourage the Government to better justify its legislation and show it has properly considered its implications.

When can amendments be made?

Parliamentary stage

When does it happen?

What happens in the Commons?

What happens in the Lords?

First reading: the formal introduction of a bill to the HouseShortly before the bill is published  The short title of the bill is read out in the Chamber. No debate takes place and no amendments can be tabled.The long title of the bill is read out in the Chamber. No debate takes place and no amendments can be tabled.
Second reading: the first opportunity for MPs and Peers to debate the main principles of the billUsually at least two weekends after publication/first readingOnly a ‘reasoned amendment’ voting down the whole bill (and providing reasons) can be made at this stage.Only amendments voting down the whole bill or expressing a view on it can be made at this stage. No reasons need be given.
Committee stage: line-by-line scrutiny of the bill


If the bill is to be debated in a Public Bill Committee:

  • on the first Tuesday after second reading (if that was on a Monday or Tuesday)
  • On the second Tuesday after second reading (if it was on a Wednesday or Thursday).

The timeframe may be compressed for bills debated in Committee of the whole House.


At least 14 calendar days after

Committee stage usually takes place in a Public Bill Committee (formed of a group of MPs and chaired by a member of the Panel of Chairs).

Important, urgent, or very minor bills may be debated in Committee of the whole House (when the bill is debated on the floor of the House of Commons). 

Amendments are routinely tabled and voted upon at committee stage. 

Amendments can be tabled as soon as second reading has finished. Amendments tabled less than three sitting days before they are due for debate might not be selected for debate. 

Committee stage takes place on the floor of the House or in ‘Grand Committee’ (where any member may speak but there are no votes).

Amendments are routinely tabled, but rarely pushed to a vote at committee stage.

Amendments can be tabled as soon as second reading has finished. They must be tabled at least two sitting days before they are due to be considered.

Report stage: opportunity to consider further changes


Usually at least a week after committee stage.

There is no Commons report stage if a bill has its committee stage in Committee of the whole House and survives unamended.


At least 14 sitting days after committee stage

Any amendment can be made.  

Amendments can be tabled as soon as committee stage has finished. Amendments tabled less than three sitting days before they are due to be considered may not be selected.

Any amendment can be made so long as it has not already been defeated during committee stage.

Amendments can be tabled as soon as committee stage has finished. They must be tabled at least two sitting days before they are due to be considered.

Third reading: the last opportunity to debate the substance of the bill.


Immediately after report stage


At least three clear sitting days after report stage

Third reading is usually formulaic.

A ‘reasoned amendment’ to vote down the entire bill may be tabled, but these are rarely voted on.  

Third reading is more substantive than in the Commons.

Amendments are limited to clarifying remaining uncertainties, improving drafting and following up earlier government undertakings. They must be tabled at least one sitting day before the stage.

Ping pong (consideration of Commons/Lords amendments)‘Ping pong’ takes place once the bill has completed its passage through both Houses. Multiple rounds can take place on same dayTo become law, both Houses must agree to the same wording of a bill. ‘Ping pong’ refers to process of a bill travelling back and forth between the Houses until all amendments are resolved.

Note: The intervals between parliamentary stages set out above represent standard practice for government bills, but can be departed from in some circumstances, including to ‘fast-track’ legislation. Intervals are usually longer for Private Members Bills.

How are amendments selected for debate?

In the Commons, the chair overseeing the debate plays an important role in deciding whether, and how, amendments are debated. Who occupies the chair varies depending on the parliamentary stage and how the bill is being considered.

During committee stage, the chair is either the Chairman of Ways and Means (the Principal Deputy Speaker) for proceedings on the floor of the House, or a chair from the Panel of Chairs (the group of MPs eligible to chair Public Bill Committees) for bills debated in a Public Bill Committee. The Speaker of the House of Commons selects amendments during report stage. The chair may group amendments together for debate. This is usually done by theme, to help structure the debate and avoid repetition.

Are there limits to what amendments can do?

The chair may refuse to select an amendment for debate if it is out of the ’scope’ of the bill, was submitted late, does not make sense, would make the bill unworkable or contradictory (a ‘wrecking amendment’), has been tabled to the wrong part of the bill or is vague. The chair must also reject an amendment that would involve spending money or raising taxes not previously authorised by the Commons in a financial resolution.

There is no selection of amendments in the Lords. This means that all published amendments can be debated. However, amendments may still be grouped for debate, by agreement between the Government Whips Office and the members who have tabled amendments. The clerks advise on whether amendments are within scope and the House ultimately decides.

How is the debate structured?

In the Commons, the time available for each parliamentary stage is usually determined by a programme motion proposed by the Government and agreed by the House after second reading. Programme motions are not used in the Lords.

Are all amendments voted on?

Many amendments are never formally moved or are moved but then withdrawn without a vote. This may be the case if MPs or Peers are satisfied with the Government’s rebuttal during the debate or if they have received assurances that concessions will be forthcoming. Other amendments may be withdrawn if they have little support. In the Commons, if the MP tabling the amendment does not move the amendment, it will not be voted on. In the Lords, an amendment may be moved by another Peer.

The Government may also accept amendments without the need for a vote.

After amendments are debated, and if they are not withdrawn or accepted by the Government, MPs or Lords will be asked to vote on whether an amendment should be accepted. Government drafting changes and other uncontroversial changes are usually agreed to without a formally recorded vote (known as a 'division').  

What happens if a bill is amended?

If accepted, amendments are incorporated into the bill. However, the bill does not have legal effect until it is given Royal Assent and becomes an Act of Parliament. Any amendment incorporated into a bill may be modified or reversed during a later stage, either in the same House, or when it is considered by the other House (when the amended bill goes to the second House, it incorporates any amendments made by the first House).

Institute for Government

Related content

01 MAR 2024 Explainer

MPs' security

Increasing levels of anti-Semitism and Islamophobia have seen a rise in threats made to MPs. So what security do they receive and how is this funded?

26 FEB 2024 Explainer

What is a manifesto?

Manifestos set out the policies a political party would deliver if they were to win an election.