Boris Johnson is preparing to send half a dozen staunch Conservative loyalists to the House of Lords, in an attempt to bolster the party’s position in the upper chamber.

The new crop of peers are unlikely to be confirmed until after the 31 October Brexit deadline – but the appointments will be read as a signal Johnson is determined to stamp his mark on parliament.

Theresa May’s resignation honours list is expected to be announced in the coming days, with rewards for several of the key lieutenants who supported her through her premiership, including her chief of staff, the former MP Gavin Barwell.

Johnson is believed to have already drawn up a list of up to six names to be submitted to the House of Lords appointments commission, which has to approve new members.

The Conservatives have 238 peers in the House of Lords – but the government can easily be defeated if the 178 Labour and 95 Liberal Democrats work together.

The previous government faced a string of heavy losses over Brexit, which paved the way for MPs to exact concessions, including on a meaningful vote. In several cases, Tory peers including the former Hong Kong governor, Chris Patten (Lord Patten of Barnes), sided with the opposition parties.

Recently, peers passed a motion tabled by Labour’s leader in the House of Lords, Angela Smith, calling on the government to establish a cross-party select committee to examine the consequences of a no-deal Brexit.

The former prime minister, Gordon Brown, has suggested that MPs should take up the idea when they return to Westminster next week, and set aside a day of parliamentary time to debate the consequences of leaving without a deal.

Johnson has been accused of plotting to override parliament since he arrived at No 10, with his chief adviser, Dominic Cummings, telling colleagues they must be ready to use any means necessary to ensure Brexit happens by the end of October.

Both the cabinet and Johnson’s Downing Street team have been packed with veterans of the successful Vote Leave campaign, stoking speculation that he expects to be fighting a general election in the coming months.

Johnson’s ministers had to agree they were willing to countenance a no-deal Brexit if necessary, after May faced a string of rebellions, including from within her own cabinet.

In a foreword to a new edition of the ministerial code published last week, Johnson insisted there must be “no misuse of process or procedure by any individual minister that would seek to stall the collective decisions necessary to deliver Brexit and secure the wider changes needed across our United Kingdom”.

During Johnson’s leadership campaign, there was speculation that he could send George Osborne to the Lords, after the former remainer gave the support of the newspaper he edits, the Evening Standard, to the prime minister’s leadership campaign.

Johnson has backed Osborne’s campaign to be the next managing director of the International Monetary Fund – though it is highly unlikely to succeed, as the EU has already chosen its own candidate.