Thousands more people can see the world's largest collection of Victoria Cross and George Cross medals in a victory for Britain's "bravest of the brave". War heroes took a stand outside the Imperial War Museum in London last week in protest over the venue’s plans to remove their gallantry gongs from public display at the end of this month to make way for exhibitions about post-World War II conflicts.

Iraq War hero Johnson Beharry, 45, the first living soldier in almost 50 years to be awarded the VC, was among veterans who slammed moves to close the "stunning" exhibition as the nation commemorated the 80th anniversary of VE Day.

Lord Ashcroft has gathered 240 VCs, the highest military decoration awarded in the United Kingdom, as well as 42 George Crosses, the highest civilian gallantry award. The first Victoria Cross was awarded in 1856 by Queen Victoria. The George Cross is bestowed on those who have displayed the greatest heroism or the most conspicuous courage while in extreme danger. Only 418 have been awarded since 1940.

Now museum bosses have retreated on their decision and agreed to keep the Lord Ashcroft Gallery, home to the Extraordinary Heroes exhibition, open until the end of September after he threatened legal action. The “common sense” decision to keep the gallery open to the public for a little longer was welcomed by Lord Ashcroft, a businessman, philanthropist and former deputy chairman of the Tory Party.

He said: "I am delighted that the gallery bearing my name will now remain open until the end of September. This will make a big difference because it will enable thousands of school children, summer visitors and many other members of the public to view the world's largest collection of Victoria Cross and George Cross decorations, well over 200 in total."

But he added: "I remain disappointed that the Lord Ashcroft Gallery will close later this year after just 15 years. The fact that it will remain open for four months longer than the IWM originally announced is an important victory for common sense. My dearest wish remains that as many people as possible come to the gallery this summer to learn about some of the incredibly brave deeds of these gallantry medal recipients from Britain and the Commonwealth."

The gallery was opened in 2010 by the Princess Royal and has proudly displayed dozens of gallantry awards form Lord Ashcroft's collection along with others either owned by or loaned to the IWM. Lord Ashcroft's original intention was to gift the medals – valued at £100million for insurance purposes – to the museum, but after the IWM announced it was closing the gallery, he ripped up the clause in his will leaving them to the public.

Lord Ashcroft built up his stunning medal collection to honour his heroic father, Lieutenant Eric Ashcroft, who stormed Sword Beach with The South Lancashire Regiment during the D-Day landings.

An IWM spokesperson said: “We are engaged in constructive conversations with Lord Ashcroft and cannot comment further at this stage.”