ED MILIBAND will today undertake a huge gamble over Labour's relationship with the trade unions by proposing to end automatic affiliation with the party for their members.

It would mean union members would have to opt in to joining the party as individuals.

The move comes in the wake of the Falkirk row over allegations of vote-rigging by Unite.

The allegations have been strongly denied by Britain's biggest trade union, led by Len McCluskey, who became involved in a war of words last week over the issue with the Labour leader.

In a keynote speech in London, Mr Miliband will portray the planned move as a bid to strengthen the party's connection with ordinary working people.

While it might give Mr Miliband his Clause 4 moment, it is a high-risk strategy.

Some three million trade unionists pay around £3 a year through automatic affiliation, bringing in millions annually to Labour coffers.

A senior party source admitted Labour could take a financial hit. In theory, this could run into millions of pounds.

Mr Miliband is hoping to make this change with the co-operation of the trade union barons.

The key question arising is whether they will agree to it, and what would happen if they did not, raising the possibility some unions may disaffiliate.

A senior party source said the leader had had conversations with stakeholders but declined to give details. He stressed it would take time and careful consultation.

Today, Labour will announce a "respected senior party figure" will work on the implementation of the planned changes and their timescale.

He will advise on whether a rule change is required, but sources suggested it would not.

This morning, Mr Miliband will say: "Trade unions should have political funds for all kinds of campaigns and activities as they choose. However, I do not want any individual to be paying money to the Labour party in affiliation fees unless they have deliberately chosen to do so.

"We need people to be able to make a more active, individual choice on whether they affiliate to the Labour Party."

The Labour leader will talk of a new direction for the party's relationship with trade union members, where they as individuals choose to join Labour through the annual affiliation fee.

He will say: "This idea has huge potential for our party and our politics. It could grow our membership from 200,000 to a far higher number, genuinely rooting us in the life of more people of our country."

As police begin to review Labour's Falkirk report, Mr Miliband will say: "What we saw in Falkirk is part of the death throes of the old politics. It is a symbol of what is wrong with politics. I want to build a better Labour party and a better politics for Britain."

A party spokesman said the matter of Falkirk was in the hands of Police Scotland and "we are going to wait for that inquiry to move forward".

Until any police investigation is completed, the selection process to pick a future Westminster election candidate for Falkirk is on hold.

Today, Mr Miliband will also announce a range of changes to the selection rules.

These will include a new code of conduct for candidates, leading to disqualification for breaches, strict spending limits for candidates and "organisations acting on their behalf" and agreements with unions so "no-one can be subjected to undue local pressure".

The Labour leader will also announce that primaries will be used to select the party's candidate for London Mayor in 2016. These will not be open primaries available to anyone but instead registered Labour supporters.

Meantime, Tory headquarters wrote to Sir Bernard Hogan-Howe, the Metropolitan Commissioner, asking him to look into allegations of possible malpractice relating to Labour selections in two London constituencies, Ilford North and Lewisham Deptford.

A Labour source said there was no evidence of alleged criminal behaviour while Unite accused the Conservatives of engaging in a disgraceful political witch hunt.