Labour’s Sadiq Khan has vowed to do all in his power to make London “better”, as he was sworn in as the new mayor.

Referring to his council estate roots, Mr Khan, the city’s first Muslim mayor, said he wanted all Londoners to have the same opportunities he has had.

Mr Khan beat Conservative Zac Goldsmith, by 1,310,143 votes to 994,614 – a margin of victory of 13.6%, giving him a larger personal mandate than either of his predecessors, Boris Johnson and Ken Livingstone.

He has announced he will step down as MP for Tooting, meaning there will be a by-election in the constituency to elect a new representative in Parliament.

The former Labour minister’s victory ends eight years of Conservative control of City Hall.

It has also given a boost to the Labour party after its poor performance in Scotland’s election which saw it slump to third place behind the Conservatives.

At the swearing in ceremony in Southwark Cathedral, Mr Khan, the son of Pakistani immigrants who was brought up on a council estate, said that as a child he “never dreamt” he would one day become the mayor of the capital.

“I’m only here today because of the opportunities and helping hand that our city gave to me and my family.

“My burning ambition for our city, that will guide my mayoralty, is to ensure that all Londoners get the opportunities that my city gave to me,” he said.

“I promise you I will always do everything in my power to make our city better. I will be a mayor for all Londoners,” he added.

He also pledged to lead “the most transparent, engaged and accessible administration London has ever seen.”

•Adapted from a BBC report. Photo shows London Mayor Sadiq Khan.