“I’m calling on the Government to urgently rethink its proposed changes to welfare,” he wrote.

“Analysis of the proposals shows that the impact will be substantial, destroying the financial safety net for too many disabled Londoners.”

His comments come as MPs aim to pass a so-called “reasoned amendment” to halt the passage of a Bill bringing in the changes.

As well as limiting the eligibility for the Personal Independence Payment to disabled people, the plans would limt the sickness-related element of Universal Credit.

Labour backbenchers in the Commons have warned that the reforms would lead to “appalling poverty”.

But Work and Pensions Secretary Liz Kendall has insisted the Government’s flagship welfare changes will create the “better future we seek to build for our constituents and our country”.

Ministers have previously said the reforms could save up to £5billion a year.

But Ms Kendall has also highlighted the moral case for the changes, arguing in the Commons: “Our plans are rooted in fairness – for those who need support and for taxpayers.

“They are about ensuring the welfare state survives, so there is always a safety net for those who need it. They’re about putting proper safeguards in place to protect the most vulnerable.

“But above all, they are about our belief that everyone can fulfil their potential and live their hopes and dreams when, collectively, we provide them with real opportunities and support.”