Gallery attendants at the Public and Commercial Services Union (PCS) plan to stage more strikes at the National Gallery.

Warders and security staff at the London gallery recently staged two three-hour walkouts in protest at low pay.

In a vote, PCS members rejected pay rises of between 2.5 and 3.79 per cent. The union said some workers’ pay fell 60p short of London’s Living Wage (the minimum wage recommended by mayor Boris Johnson) of £7.60 an hour.

A National Gallery spokeswoman said: “All gallery assistants receive basic pay and premium pay for working weekends. This means the vast majority [81 per cent] of staff are earning very close to £7.60 per hour.”

The PCS also organised a separate 48-hour strike last month, setting up picket lines at institutions such as Tate Britain. “This dispute is over changes to the civil service compensation scheme, which will see staff robbed of up to a third of their entitlements if they are forced out of a job,” said a PCS statement.

The union said these measures would affect all staff. Another strike was planned for 24 March.

The Cabinet Office, which is overseeing civil service reform, said: “The 46 per cent of civil servants who earn £20,000 or less will be little affected by the changes, in that they can still receive up to three times their salary [if made redundant].” It claimed about 70 per cent of PCS members decided not to take part in the strike.

Meanwhile, employees of Culture and Sport Glasgow, which oversees nine museums in the city, are being balloted over strike action.

The trust’s proposals include a pay freeze and payment of all overtime at single-time rates, according to a spokesman for the Bectu trade union. If strike action goes ahead in mid-April as planned, “museums will close”, he warned.

A spokesman for the trust said: “We are committed to protecting jobs and services, but the reality is that we must find savings of £3.4m in the next year. So we are looking to implement more flexible working and cut overtime.”