"It's ridiculous! This is an example of the government being anti-London," Sadiq Khan told ITV News London
London Mayor Sadiq Khan dismissed a "ridiculous" claim by Transport Secretary Grant Shapps he breached election rules by confirming the Elizabeth Line opening date a day before local elections.
The Cabinet minister accused Sadiq Khan of "breathtaking political cynicism" after it was revealed the £19bn underground Crossrail route would open on 24 May.
Mr Shapps said: "This announcement is an act of breathtaking political cynicism by the Mayor, breaking election rules on such announcements in an effort to garner votes the day before the local elections in London.
"I am therefore immediately referring this breach to the Electoral Commission for investigation.
"Londoners reading this unscrupulous headline grab might like to know that the Government has poured billions into Crossrail to solve delays clocked up on the Mayor’s watch, while propping up a transport system hobbled financially by his chronic incompetence."
Around 30 minutes after issuing the statement, Mr Shapps posted a message on Twitter stating the Elizabeth line will open "thanks to £9bn of Government support".
He added that it will "transform the lives of Londoners for generations to come and deliver a £42 billion boost to the whole UK economy".
The total cost of Crossrail - the project to build the railway - has been estimated at £18.9 billion.
Crossrail Ltd says this includes £5.1 billion from the Government.
The Government has also provided nearly £5 billion to TfL to keep services running during the coronavirus pandemic.
But Sadiq Khan brushed aside the criticism and told ITV News London the government should "join the party" and stop being "anti-London".
"It's ridiculous! This is an example of the government being anti-London, they should join the party and welcome this new fantastic line opening in the same year as the Queen's Platinum Jubilee," Mr Khan said.
"Paris, New York, Chicago and Madrid are green with envy at this great new line opening on 24 May," he added.