The government should stop "putting dogma ahead of the national interest" and extend the Brexit transition period, Sadiq Khan has said.
The Mayor of London broke Labour ranks on Monday to call for the delay past the end of the year, given the lack of progress in negotiations and disruption caused by the coronavirus crisis.
Boris Johnson has refused to sign up to a longer transition, despite it being an option under the treaty he negotiated. The formal deadline for extending the period is the end of this month, with the transition itself due to expire at the end of the year.
If no trade agreement is signed or there is no extension then the UK will crash out of the single market on 31 December and face high tariffs and long queues as Dover and Calais - with serious economic damage and disruption to trade expected.
Mr Khan's intervention is notable because Labour leader Keir Starmer has said he is not calling for an extension to the transition period, despite the looming deadline this month.
"The Government’s negotiations with the EU and other countries are highly unlikely to progress towards meaningful results and agreements while the pandemic continues," Mr Khan said in a letter to cabinet office minister Michael Gove.
"An extension to the transition period is now urgently needed to give businesses and public services some certainty that they won’t face the threat of another cliff edge in six months’ time.
"Otherwise the Government risks undermining the unprecedented steps it has taken to protect jobs and livelihoods, by prolonging uncertainty about our economy and the terms on which future trade will be conducted."
Mr Khan added that "one anticipated when voting for Brexit that the key negotiations would take place at a time when all governments are rightly focused on fighting a global pandemic".
He added: "The last thing the country needs as it tries to find a way back from the devastation wreaked by Coronavirus is more chaos and uncertainty. I urge the Government to put political ideology aside and pursue the pragmatic route of seeking an extension to the negotiations so that we and our European partners can focus on recovery from Covid-19.
"Covid-19 is the biggest health, social and economic emergency we have faced since the Second World War. Further disruption, in the form of tariffs, red tape and new immigration rules when we leave the single market and customs union at the end of the year, would be needless and hazardous. Close regulatory alignment with the EU has never been more vital to protect our economy and support its recovery from the impacts of Covid-19."
Trade talks are getting underway again from Tuesday this week, after the previous round last month ended in deadlock yet again. Fishing is set to be high on the agenda, with the EU insisting that its mandate will not change to suit UK needs.
Other issues on the agenda including trade in goods and services, as well as the so-called "level playingfield" on regulations, and whether Britain will be able to participate in certain EU programmes.
The main sticking points in the talks so far are the extent to which the UK will stay aligned to EU rules, the involvement of the European Court of Justice, and whether Britain will commit to maintaining its human rights standards – as well as fishing rights for EU fleets.
Mr Khan joins other opposition parties like the Lib Dems and SNP who this weekend reiterated calls for an extension.
“We are in the midst of a health pandemic and businesses are already struggling to survive. They simply do not have the ability to also prepare for a hard or No-Deal Brexit in just a few months’ time," said SNP Shadow Brexit spokesperson Dr Philippa Whitford.
She said dubbed UK government policy a "reckless Brexit obsession" and called on ministers to "step back from the brink and prioritise people’s safety, their livelihoods and the economy" with an extension.
Lib Dem MP Layla Moran said: "People and businesses have suffered enough this year. Our economy will still be on the ropes from Coronavirus in December, and a No Deal Brexit would only worsen the stress and anxiety that many employees and business owners already feel.
Speaking on 11 May Labour leader Sir Keir said: "I’ve not called for a pause because the government says it’s going to get it done by the end of the year. So let’s see how they get on."