Sadiq Khan’s City Hall office was told it could be prosecuted for flying the EU flag on the anniversary of the Brexit referendum as a goodwill gesture.
The London mayor’s office wanted to display the flag in solidarity with the capital’s European residents seven years after the referendum decision to quit the bloc.
But officials dropped the plan after being told they would have been liable to criminal prosecution without special permission from Newham council because the government has changed regulations.
“With over a million people calling London their home from other European countries it’s extraordinary that the government has effectively banned the European flag being flown without going through a long and bureaucratic planning process,” said a City Hall source.
“Europeans contribute hugely to our social and economic life, and all we wanted to do was show our gratitude with a small gesture for one day of the year.”
The City Hall building in Southwark will now use blue and yellow lights to mark the Brexit anniversary on Friday.
The EU flag did not require any special permission until changes were made to town and country planning (control of advertisements) regulations in England after Brexit.
In a letter to Londoners from EU countries, Mr Khan said the Brexit vote had been a “heart-breaking day for me, and I know it was for many of you too”.
He added: “There is no doubt that in the years since, Brexit has caused huge damage to our city and created a great deal of uncertainty for many of you. But you stayed with us.”
The Labour mayor – who put himself odds with his party after calling for Britain to rejoin Brussels’ single marker – said he backed Keir Starmer’s call for EU citizens to get the right to vote in general elections.
Ahead of the Brexit vote anniversary, Labour’s foreign secretary David Lammy hinted that the party’s policy could inch forward to even closer ties with Brussels.
Although Labour insists it will not re-join the single market or customs union, Mr Lammy told LBC the approach of seeking a veterinary deal to ease food trade is a “floor not a ceiling” and said he wants “to hear what business has got to say over the coming months”.
It comes as former Brussels negotiator Michel Barnier told The Independent that the EU would be willing to thrash out new treaties with the UK in areas like security, defence or development where Boris Johnson “refused to negotiate”.
Writing for The Independent, Mr Barnier also dismissed suggestions that blockages to trade could be resolved without membership of the single market or customs union – dashing hopes of some British businesses that have struggled under the new arrangements.
Gina Miller, one of the leaders of the Remain campaign, set out a three-year blueprint for how Britain could rejoin the bloc in The Independent, while Tony Blair’s think tank has spelled out 10 areas where a closer economic relationship could take shape.
More than 50 per cent of people believe that the UK was wrong to leave the EU seven years on from the referendum, according to a new Deltapoll survey for the Tony Blair Institute.
Meanwhile, at least 20 per cent of Brexit supporters would vote differently if they were asked now, a poll of hundreds of people on BBC Question Time has found.
One audience member, who admitted he would vote differently now, said: “I don’t see any benefit from it all”, while another blamed the efforts of politicians to “frustrate” the process and said: “We haven’t started Brexit yet, when’s it going to start?”
Former No 10 press secretary Alastair Campbell received a round of applause from the audience for his opening comments in which he said the British public were “lied to” and called for Boris Johnson to be held accountable.