Image caption Nick Clegg has said the House of Lords does not belong in the 21st Century

MPs and peers are preparing to throw out government plans to slash the size of the House of Lords.

Ministers want to cut the Lords to just 300 mostly-elected members as part of a radical reform of parliament.

But a joint committee of MPs and peers examining the government's plans has concluded that the Lords should have around 450 members.

They will argue the Lords cannot work effectively with just 300 members to do the work of scrutinising legislation.

"You just cannot do it with 300," said one committee source.

Expertise

They will also claim that a smaller Lords would leave the second chamber with too few independent, cross-bench members.

Under current plans, just 60 out of the 300 total would be appointed for their knowledge and expertise, rather than elected for their political allegiance.

Simply cutting it back to 300 and assuming that everybody's got to be a full time parliamentarian, would make us too much like the House of Commons. Lord Tyler, Lib Dem peer

Some on the committee also believe that a larger Lords would mean that smaller political parties and independent candidates would have a better chance of getting elected to the reformed second chamber.

One Lords source said: "It is the agreement of the committee that we are working on the hypothesis that 450 works better all round."

Although there are in theory some 788 peers currently able to sit and vote in the House of Lords, only about 400 are regular attenders.

The committee's recommendation for a larger Lords challenges a fundamental principle of the government's draft bill, namely that members of the reformed house should be full-time parliamentarians.

Part-time

The committee believes that many members should be part-time and able to keep outside jobs so that they can maintain their expertise for their 15-year terms.

Lord Tyler, a Lib Dem peer on the committee, told BBC Radio 4's Today programme: "Simply cutting it back to 300 and assuming that everybody's got to be a full time parliamentarian, would make us too much like the House of Commons.

"And I think the public are expecting to have a second chamber which is very different to the House of Commons, where there could be people who are still experts in their field, keep up with their professional or business background, while they are members of the second chamber of Parliament.

"And to do that, clearly, you cannot have everybody, every day, working in a House of Lords. "

The committee on the Draft House of Lords Reform Bill is expected to publish its conclusions in March.

The government will not be bound by the committee's decisions but disagreement over such a fundamental issue as size will make it harder for ministers to achieve consensus around the final bill which they hope to introduce to Parliament in the Queen's Speech this summer.

Timing

The timing is crucial as there will be overwhelming opposition to any reforms in the House of Lords.

If the government does not get a bill into Parliament this year, then it would subsequently be hard for ministers to use their powers under the Parliament Acts to force the legislation through the Lords by the time of the next election in 2015.

The committee is also likely to challenge Clause 2 of the Bill which asserts that the reforms would not change the relationship between the Lords and the Commons, specifically not affecting the primacy of the House of Commons.

Some committee members believe that this assertion will not wash and there needs to be a specific new framework put in place that would allow a largely elected Lords to be more assertive without threatening the primacy of the Commons.