Again, support by over 250 members of the Prospect and Public and Commercial Services unions was strong with pickets outside five of the museum’s sites.

They are fighting an imposed pay offer worth 1.8% for 2007 and 1.3% for 2008, less than half the rate of inflation.

"The public reaction has been overwhelming," said Prospect negotiator Tony Hammond. "What is encouraging for the staff in dispute is that their campaign is developing momentum. Not only among the public, but also MPs – 18 of whom have now signed the early day motion put down by Bob Wareing, MP for Liverpool West Derby."

Hammond said that Liverpool councillor and labour group leader Joe Anderson had turned up on the picket line to support striking staff and their campaign.

"He pledged he would place a motion before the council on September 5 urging NML to return to the negotiating table with the unions to end the dispute amicably," said Hammond.

"There is growing dissatisfaction in the city that NML have taken pride in their stance that they are a low pay employer. The museum has seriously misjudged the mood of staff, the public, the local council and MPs.

"It is surely time for NML management to swallow their pride and enter new talks on pay."