Striking rail workers are to stage a protest outside the Department for Transport amid claims that the Government has put a "blockade" on talks to end a row over the role of conductors.

The Rail, Maritime and Transport (RMT) union stepped up its attack on the Government over the bitter dispute at Southern Railway.

Hundreds of thousands of rail passengers faced a second day of disruption because of an RMT strike which continues until Friday.

Southern Railway have already cancelled trains from Watford Junction for more than four weeks now.

The union said it was "within an inch" of reaching an agreement during talks last week at the conciliation service Acas.

It repeated its claim that the Government had "sabotaged" any deal, and again named Transport Department official Peter Wilkinson as "directing operations from outside".

The Department denied the claims.

The union said a deal was being discussed based on an offer made last week by ScotRail in a similar dispute which led to strikes being suspended.

RMT general secretary Mick Cash said: "RMT can confirm that we were within an inch of making progress towards boxing off a deal with Southern in Acas talks on Friday afternoon that was based on the offer from ScotRail, an offer that enabled us to suspend all industrial action in the ScotRail guards dispute.

"We were just getting into the detailed wording when suddenly the plug was pulled and our legs were kicked from under us.

"We have it on good authority that the deal, which would have enabled us to suspend the Southern strike action this week, was sabotaged by the Government with their director of rail, Peter Wilkinson, directing operations from outside the talks.

"We are now taking our protest direct to the DfT.

"We want the Government to stop weaponising the Southern dispute for political purposes and we want them to stop treating passengers and staff as collateral damage in a war that Peter Wilkinson has unilaterally declared on the rail unions."

The protest will be held on Wednesday.