George Osborne and Nick Clegg have been spotted having lunch near Westminster, fuelling speculation they may be coordinating efforts to avoid a hard Brexit.

The former chancellor and former deputy prime minister had an often difficult relationship in the Conservative-led coalition government, particularly towards the end, with Clegg describing Osborne as a very dangerous man whose behaviour was “very unattractive, very cynical”.

But the pair appeared to put aside their differences to meet at the Cambridge Street Kitchen in Victoria on Tuesday, where they were photographed having a glass of wine. A picture and short footage of their meeting was later published by LBC.

Remain campaigners George Osborne and Nick Clegg spotted meeting in Victoria restaurant https://t.co/Lim5Fsvfty pic.twitter.com/5qhbhU00PU — LBC (@LBC) December 20, 2016

The restaurant, whose slogan is “Why hello, Pimlico”, is a casual gastropub-style venue slightly off Westminster’s beaten track, where a beefburger costs £14.50 and dishes such as a soft-shell crab burger and an open salt-beef sandwich also feature.

A Lib Dem spokesman would not comment on the subject of the lunch other than to say it was private.

Both politicians supported staying in the EU and have decided to remain in public life despite losing their government jobs.

Osborne has not formally taken part in meetings of the Tory MPs pushing May to keep the UK close to the single market but is known to be influential behind the scenes.

He has repeatedly warned about the potential economic dangers of a hard Brexit, saying: “What the future tells you at the moment, and what financial markets tell you today, is that every time they think Britain is going to have a less close relationship with our trading partners in Europe – every time there’s a hint from the government or a government minister says something like that – then the pound falls and in effect, the world is betting against Britain.

“Every time you have thoughtful contributions from members of the government saying: ‘Well actually we need some kind of transition, we do need to have something more than the World Trade Organisation rules’ – every time you hear something like that – the world bets on Britain.”

Meanwhile, Clegg has taken on the role of Brexit spokesman for the Lib Dems and has released a series of detailed papers examining issues such as the likely impact on food prices and the potential effects of leaving the jurisdiction of the European court of justice.