The Victorian industrialist Lord William Armstrong was a passionate art lover who collected hundreds of paintings and sculptures to display in his grand Northumberland home.

But visitors hoping to admire his celebrated collection at a National Trust exhibition were furious to find ‘room after room’ of artwork covered with white sheets.

The trust, which owns Lord Armstrong’s former home of Cragside, covered up paintings and sculptures depicting men to highlight the ‘lack of female representation in art’.

Cragside in Northumberland draped a number of paintings and sculptures showing men with white sheets or plastic bags to highlight the marginalisation of women in art

This poster was put up on the wall to explain the thinking behind the 'Women in Power' exhibition

It meant visitors who had paid up to £49 to view the famous collection found almost half of the paintings hidden behind white sheets, while sculptures of men had bags placed over their heads.

One said: ‘It was ridiculous. Whole corridors and room after room were completely covered.’

It was part of the National Trust’s Women and Power programme for the centenary of women’s suffrage. The three-week exhibition, which ended on Sunday, was designed to encourage visitors to ‘notice the absence of the female voice’ by ‘concealing male representation’.

But it was so unpopular that staff reportedly had to empty the visitor comments box three times a day because it was overflowing with complaints.

The trust initially defended the ‘thought-provoking exhibition’ but later admitted: ‘Sometimes it doesn’t work as we intended.’

A statue on the upstairs floor at Cragside covered in a plastic sheet (right) was just one of a number of art works covered up (left)

Art works at the Victorian country house in Northumberland (pictured), which belonged to Baron Armstrong, were covered up as part of the National Trust's 'Women in Power' exhibition

Sir Roy Strong, 83, former director of London’s Victoria and Albert Museum and the National Portrait Gallery, said: ‘Lord Armstrong would be horrified to see his art being used to deliver a diatribe on political correctness.

‘His art collection was given to the National Trust in good faith. The fact they have gone on to use it in this way will be extremely off-putting to any future donors.’

He added: ‘If the public pay to see an art collection they expect to see what is there.

‘It’s insulting … to censor paintings to make a political point. I find the whole thing infantile and rather sad. It is completely pointless. I’m sure the donor would be turning in his grave.’

One visitor, Jim Herbert, said: ‘Having paid a touch under £50 to get in, it is disappointing not to see the whole collection.’

Another, Sharon Wilkinson, 64, accused the National Trust of ‘abusing something in their care’. She added: ‘Believing that the only way to put women forward is to put men backwards is mad.’

Scott Anderson, 36, added: ‘This is just PC for PC’s sake. Covering up male art is not going to achieve equality.’

The collection at Cragside, acquired by the National Trust in 1977, includes paintings by JMW Turner and Raffaello Sorbi. A trust spokesman said: ‘This temporary student exhibition at Cragside was not about censoring art or being politically correct, but to encourage people to look at the collection differently and stimulate debate.’

The trust has been embroiled in a number of rows over political correctness, including asking volunteers to disclose their sexual and gender orientation and making some wear gay pride badges.

Some visitors were angry at having paid up to £49 for entry but being unable to see all the artwork