London, March 27 (Reuters): Up to 1.5 million British local government workers are planning to strike tomorrow, closing thousands of schools and disrupting travel in what unions say will be the biggest action since the 1926 General Strike.

Eleven labour unions have combined for the 24-hour protest over retirement rights and cuts to pensions.

The action will close at least 70 per cent of schools in London as teaching assistants, caterers and cleaners stop work. The school attended by Prime Minister Tony Blair’s son Leo will also be closed.

At issue is the government’s decision to scrap the so-called 85-year rule, which states that members of the Local Government Pension Scheme (LGPS) can retire at 60 on a full pension if their age and years of service add up to 85 or more.

Employees in the scheme include carers, charity workers, refuse collectors, leisure centre workers and people who work in call centres, environmental services and housing associations.

Tony Woodley, general secretary of the Transport and General Workers Union (T&G), said they were shocked at the law change. “Three quarters of those workers are women, and it is no accident that the government has chosen not to protect their pensions in the way it agreed last year for the civil service, the NHS, teaching and others,” he said.

“Any of those who’ll stop work tomorrow are in the front line of providing care for older people and for children. It is a measure of their anger that they’ve been driven to take this strike action.” At least one airport, Leeds Bradford, will be affected as some staff join rallies to protest, and bus services in Scotland, Northern Ireland and Wales will also be disrupted.