Scottish veterans who have been denied the right to wear medals they won fighting a bitter jungle war against communist insurgents reacted angrily yesterday to the news they have finally been granted "temporary permission" to display the awards.

The veterans, who fought in the 1950s and 60s, can only wear the Pingat Jasa Malaysia medal for 25 days - and only if it is worn on Malaysian soil as part of that country's celebration of 50 years of independence later this month.

Even then, the old soldiers who spent two years of their lives in some of the most inhospitable terrain on Earth to underpin that independence have been told that the PJM decorations will immediately become banned again after those few days' grace.

It means the awards from a grateful Malaysian government still cannot be worn at Remembrance parades or other military functions in the UK.

The veterans have been fighting for two years for the right to include the PJM with their other medals, but have been told that "foreign" awards are unacceptable and that a British general service medal is available for those who fought in Malaya. Some have even been considering suing the Cabinet Office for "maladministration".

Now Tanya Collingridge, honours' secretary at the Foreign Office, has announced that the PJM may be worn by old soldiers travelling to Kuala Lumpur, the Malaysian capital, for the independence celebrations. Campaigners representing the eligible 35,000 former UK soldiers, sailors and airmen - including an estimated 5000 Scots - say a handful of unelected civil servants are denying them an honour they earned against the communists.

Despite a 1968 ruling by the Queen that orders, decorations and medals conferred on UK citizens by Commonwealth countries could be worn "without restriction", the Cabinet Office's seven-member honours and decorations committee has spent much of the past two years obstructing the process.

The committee finally ruled in 2006 that eligible veterans, most now in their 70s, could receive the PJM medals, but not wear them publicly.

Yet last year the government granted permission for the award and wearing of medals for the 1956 Suez campaign and allowed Russian medals to be pinned on British survivors of the 1940s Murmansk convoys.

The Malayan "emergency" was never raised to the status of a war because that would have rendered void insurance on British-owned rubber plantations and railways, both insurgent economic targets. It was a full-blown guerrilla war waged by ethnic Chinese Communist guerrillas against British and Commonwealth forces for more than a decade.

A total of 519 British troops were killed, including 95 Scots, in more than 10 years of ambushes and patrol actions in jungles, mountains and swamps. Thousands more were wounded or fell sick.

The Malaysian government offered to supply the campaign medals at its own expense in 2005 to honour the Commonwealth troops who defended its existence and sovereignty.

The governments of Australia, New Zealand and Fiji all accepted the offer and their Malaya veterans can now wear the PJM alongside their other decorations.

A spokesman for the Foreign Office said: "Her majesty's government's rules preclude the wearing of foreign medals for events in the distant past or for events more than five years previously."

Andrew Nicoll, one of the leading Scottish campaigners, said: "The unaccountable honours and decorations committee seems to be making up the rules as it goes along. Its members have already contradicted their own regulations several times. The bottom line is that this medal was fought for and earned with the blood of young British soldiers, many of them National Service conscripts. The committee is treating their memory with contempt. It is also insulting the Malaysian government's generosity."