A loophole that allows MPs to rent out a London property they own while billing taxpayers for living at another address in the capital should be closed, Tory MPs have said, in an effort to avoid sleaze scandals dragging parliament’s reputation down further. Senior politicians, including the longest-serving member of the House of Commons, Sir Peter Bottomley, told the Guardian the system was in urgent need of reform to make it fairer for taxpayers and MPs. The call came after the former attorney general Geoffrey Cox was discovered to have rented out his three-bedroom flat in south London for up to £4,000 a month while claiming £1,900 a month in rent for a separate residential property. He was not breaking any rules. Reportedly about a dozen MPs rent out a private property in London while claiming for rent at another location so they have somewhere to stay during the week. Changes made after the expenses scandal in 2010 mean MPs are unable to claim mortgage repayments on a property they own in London, meaning those who already had a home in the capital had to rent elsewhere if they wanted to claim expenses for the cost of having somewhere to live near Westminster. Some MPs who do just that are among the system’s harshest critics, and argue that the bill to taxpayers from having to rent out another property is higher than if they had just remained living in the original one they owned and billed the mortgage repayments instead. Bottomley said he was not personally affected by the loophole, but that the rule change that created the loophole was “arbitrary” and the issue thrust into the spotlight by Cox’s situation “has been building for 10 years”. “I think they should adapt it,” he said, pointing to other changes the Independent Parliamentary Standards Authority (IPSA) made to the conditions on how MPs could claim for accommodation since the original rules came into force. “IPSA should consult with the parliamentary Labour party, the 1922 Committee [the Conservative parliamentary grouping], and other opposition parties to create a system that is fair to the taxpayer [and] MPs.” A minister said it would “help show we’re genuinely trying to save taxpayers money”. And other Tory MPs said it would make the system fairer, with one suggesting they be allowed to claim for mortgage interest payments and then share any profits on the resale of a property to ensure fairness for taxpayers. Sir Alistair Graham, a former chair of the committee on standards in public life, said: “The loophole needs to be closed. MPs have got a personal responsibility to only use public funds where really necessary. If they have flats in London then they shouldn’t call on public funds, simple as that.” In a statement, IPSA said: “After public consultation in 2017 it was decided that an MP’s personal financial situation is not a relevant test for whether they should receive support for their parliamentary duties. Our statutory responsibility is to ensure that MPs have the appropriate support they need, including suitable accommodation. IPSA keeps the rules, and compliance with them, under constant review.” Boris Johnson continues to face the fallout from a scandal that began with him trying to save a Tory MP from suspension for breaching lobbying rules, and has now snowballed to place scrutiny on other Conservatives’ business interests. In an attempt to improve relations with Tory backbenchers, all those elected in 2019 have been invited to a reception at No 10 next Tuesday. The deputy chief whip wrote to them all on Friday demanding an end to negative briefing against the government to the media, adding: “It is rarely helpful to provide commentary.” The chief whip, Mark Spencer, has not cleared his weekend diary to ring round MPs and smooth over tensions, as some MPs had expected. He is instead due to attend a charity shooting event.