Boris Johnson has been criticised for the swelling size of the House of Lords and an imbalance in the political make-up of the upper chamber.
A report from the Lord Speaker’s committee on the size of the house highlighted Mr Johnson as showing “no interest” in trying to reduce the number of peers.
It was suggested six years ago that the Lords adopt a one-in, two-out system – for every two people left, only one is appointed.
While Theresa May “responded positively” to this, and “progress” was made up to 2019 in reducing the ermined headcount, the committee singles out Mr Johnson for criticism.
“Prime Minister Boris Johnson showed no interest in the issue of the size of the House,” the report said.
“While the number of departures from the House continued to be broadly in line with our benchmarks, the number of appointments far exceeded them and they were granted predominantly to members of his own party.”
The report also noted that the House of Lords Appointments Commission rejected more than half of Mr Johnson’s initial nominees, and raised concerns about the party balance in the Lords and the potential for Labour to appoint swathes of peers should they win the next election.
Labour peers currently make up just over 20% of the House of Lords, with this number still under 30% when bishops and crossbench – those not aligned with a specific party – members are not included in calculations.
To illustrate the rate of appointments in recent years, the committee noted that despite 175 deaths or departures in the period, 168 new peers were added.
Under their one-in, two-out formula, this number should have been 88 – but instead, 88 Conservatives peers alone have been added.
As part of its recommendations, the committee wants to see a cap on the membership of the Lords, which is currently unlimited, a fixed term for service – with a suggestion of 15 years, and a fair allocation of new appointments based on recent election results.
The report also singled out the way in which hereditary peers are still entering the Lords as incompatible with the modern age.
All 90 of the allocation are men, and there are no propriety checks on new entrants.
Hereditary peers – the remnant of the landed aristocracy who automatically take seats in the legislature – hold by-elections when one of the 90 slots becomes available.
The committee called for these elections to be scrapped.
The chair of the Lord Speaker’s committee on the size of the house, Lord Burns, said: “There is widespread support in the House of Lords for our core proposals, first published in 2017.
“We must now learn from the problems we have seen over the past six years which, if they were to continue, could see the House becoming even bigger than now.
“The political leadership should focus initially on putting in place a sustainable and fair method of allocating appointments.
“This will set the basis for a cap and a sustainable reduction in the size of the House.”
The Lord Speaker, Lord McFall of Alcluith, said: “The scrutiny and revision role of the House of Lords is crucial to effective law-making, and this task is underpinned by the expertise and experience which individual peers bring to their work.
“This report by a cross-party committee of peers provides recommendations which would reinforce the reputation and effectiveness of the Lords. I hope they will be considered seriously and carefully.”