One of the main unions representing museum specialists, Prospect, has slammed the potential further cuts of up to 15% being considered by the Department for Culture, Media and Sport (DCMS) as "illogical".

DCMS-sponsored bodies, including national museums, have been asked to model further cuts of 5%, 10% and 15% in advance of the spending review on 26 June, which will set out government spending plans for 2015 onwards.

These reductions would follow a 3% cut in the emergency budget of 2010, 15% cuts in 2011 and baseline cuts of 1% in 2013/14 and 2% in 2014/15.

The Science Museum Group warned last week that it would be forced to close one of its northern museums if cuts of 10% or more were implemented.

Prospect’s national secretary Alan Leighton said: “The financial logic for such cuts is baffling, given that every £1 spent on the arts generates £4 for the economy. We are talking about organisations that make a major contribution to the UK.”

Leighton criticised some media coverage of the spending review, which he said gave the impression that “the cuts are only just getting started”.

He said: “These organisations have already implemented substantial cuts to their activities, including significant job losses and pay freezes. Further cuts of the magnitude suggested are bound to make organisations consider introducing charges and closing museum branches or floors.”

Speaking to Museums Journal, he added: “Museums have pretty much gone through the fat – which wasn’t even fat to begin with – and they are now cutting down to the bone.”

Cuts of 15% would result in "carnage", he warned.

Leighton said that the union had seen an exodus of skilled staff from the museum sector due to pay freezes and redundancies.

“Museums are losing valuable staff. We are seeing a lot of people with transferable skills moving to other sectors and a lot of people who have decided to retrain.”

These losses would have a knock-on effect on the reputation of UK culture and tourism, he warned.

Staff at several institutions have taken industrial action in recent weeks over pay and working conditions in a campaign organised by the Public and Commercial Services union.

This has included strikes at National Museums Liverpool and London’s national museums, as well as staff walkouts at a number of English Heritage sites.

The industrial action campaign is due to culminate in a national walkout at the end of June.