Defiant RMT union members plan to protest outside the London headquarters of the Department for Transport amid a five-day-long strike by guards on Southern Rail. The union claims the government has implemented a "blockade" on a potential peace deal between its officials and Southern operator Govia Thameslink Railway (GTR).

"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," said Mick Cash, the general secretary of the RMT.

"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 government need to lift the blockade on the peace talks and allow us to get back to normal industrial relations and serious and meaningful talks with the company. If it's good enough for Scotland it should be good enough for the rest of the UK as well."

The comments come as tens of thousands of commuters are faced with travel misery over the walkout. The dispute is over proposed changes to the roles of conductors on Southern Rail trains.

The disruption is expected to result in around 40% of normal services being cancelled across Southern rail lines. RMT officials and Southern Rail bosses held talks at mitigation service Acas until the negotiations broke down on 5 August.

The RMT told IBTimes UK it has no plans to restart talks, while GTR insisted it offered the union a number of concessions in a bid to avert the strike. "Last week we offered the RMT a significant, four-point compromise plan," a spokesperson for the operator said.

"This involved a number of assurances to the RMT relating to job security, guaranteed voluntary overtime and a joint review of the role after 12 months. We also offered to agree a list of rules which governs when the train can and can't run without a staff-member on board, but the RMT refused to even discuss this.

"We apologise sincerely to our passengers for the disruption the RMT is causing them. However, we are progressing with implementing this new role and this will begin later this month. We are gradually introducing new and more modern trains with more capacity. We are running the biggest ever driver training programme in the UK rail industry. We are focusing station management teams on further reducing delays at station."

The Department for Transport had not responded to a request for comment at the time of publication.