The National Gulf Veterans and Families Association claim more needs to be done to support former soldiers who are suffering from chronic headaches, cognitive difficulties, depression, unexplained fatigue, rashes and breathing problems.

Maria Rusling from the association told Sky News: "Although some veterans are on war pensions and benefits, a lot of them are still fighting not only the benefit system but the illnesses they have."

Thousands of troops from Britain and other countries fell ill with what is sometimes called Gulf War Syndrome, after the conflict began two decades ago.

During the war allied forces launched a massive bombing campaign, which led to victory over Iraq.

A soldier fighting in the Gulf War

A US soldier patrolling Kuwait during the Gulf War

The assault began a more widespread offensive - Operation Desert Storm.

It led to Saddam Hussein's forces leaving Kuwait, having invaded on August 2,1990.

Coalition soldiers then entered Iraq and advanced 150 miles from Baghdad before President George Bush Snr declared a ceasefire.

The move proved to be controversial.

Saddam continued to be a thorn in the international community's side leading to the second Gulf War in 2003, when Allied forces controversially invaded Iraq and brought about his fall.

A grave honouring those who died in the Gulf War

A grave in Iraq honouring those who died during the Gulf War

He was hanged in December 2006 for crimes against humanity.

The coalition in the first war was composed of 34 nations, led by the US and UK.

Iraq's invasion of Kuwait had brought international condemnation, which was aggravated when Saddam appeared on state television with Western hostages whom he appeared ready to use as a human shield.

On November 29, 1990, the United Nations passed a resolution giving Iraq until January 15, 1991 to withdraw.

When the air campaign began, the coalition flew more than 100,000 sorties, dropping 88,500 tons of bombs.

Saddam Hussein

Saddam Hussein during the Gulf War

Saddam declared that "the mother of all battles has begun".

The Allies' first aim was to destroy Iraqi air force and anti-aircraft facilities. They also attacked command and communication centres and launchers for Scud missiles.

Iraq fired missiles into Israel, but Tel Aviv complied with a US request for non retaliation, helping to keep Arab states in the coalition.

The air blitz was followed by land attacks into Kuwait from February 23.

Coalition fighters met generally light resistance before the Iraqis were expelled. But before they left, they torched nearly 700 oil wells.

Operation Sandstorm

A tank near a fire in an oil field in Kuwait during the first Gulf War

The coalition advance into Iraq was more speedy than US generals had expected. Forces from the US, UK and France chased retreating Iraqi forces over the border before Mr Bush declared a ceasefire on February 28.

In 2009, a landmark study for the US Congress concluded that troops' ill-health was caused by them being given nerve gas pills and exposed to pesticides during the conflict.

The Ministry of Defence's official position has been that Gulf War Syndrome is a useful "umbrella term", but comprises too many different symptoms to be characterised as a syndrome in medical terms.

Veterans' representatives say this has led to difficulties in receiving pensions.

The MoD has said claims are dealt with as quickly as possible.