British regiments serving in the mixed desert and fertile terrain of Helmand province in southern Afghanistan have fired millions of rounds of ammunition during hundreds of clashes with the Taleban in the past two years.

Close combat machine gun exchanges, roadside bombs, landmines and the dropping of precision-guided 500lb bombs from RAF Harriers and American F16s have created a cacophony and stretched military and medical resources.

The statistics of the war in Helmand already make grim reading: 121 members of the Armed Forces have died, 94 of them killed in action.

About 500 have been injured in battle, 150 of them categorised as “very seriously” or “seriously” wounded, and 34 have suffered amputations, mostly as a result of roadside bombs and landmine explosions.

Behind these statistics, however, lie the lasting health problems that do not make the headlines.

The Times has unearthed startling statistics on hearing problems through a series of Freedom of Information requests.

Although the Ministry of Defence was unable to provide figures for all regiments, the findings of our investigation suggest that most combat units sent to Helmand can expect to be affected.

The MoD has five gradings for hearing capacity, ranging from “good” and “acceptable” to “impaired” which is grade three, to “very poor” and “invalidity required”.

Many of those suffering hearing problems are undeployable, although the MoD could not give a breakdown of those who had to be discharged or given desk jobs.

An insight into the scale of the injury toll on individual regiments was highlighted in a written Commons answer on October 20, when it was revealed that every battalion is suffering from a high number of unfit soldiers. This includes personnel who have returned from Afghanistan with debilitating injuries and health problems, such as deafness.

The findings are disturbing: 37 out 411 soldiers in the Grenadier Guards, 240 of the 1st Battalion The Royal Anglians, including 35 categorised as either undeployable or with limited deployment potential, and 34 out of 555 soldiers in The 2nd Battalion The Mercian Regiment (Worcesters and Foresters) are suffering from hearing ailments. All are listed as suffering from grade three loss of hearing or below.

The Royal Marines have just taken over the main role in Helmand, their second tour of duty in two years – and deafness is still affecting many of the troops from the first tour, which finished 18 months ago. According to the MoD, as of September 12 this year 45 Commando Royal Marines, which returned from Helmand in April last year, reported that 31 out of 963 personnel had hearing defects, all of them at grade three or below.

Similarly, 40 Commando Royal Marines, which completed its tour of duty in Afghanistan in April, serving with 52 Brigade, has reported that 28 Marines out of a strength of 771 are suffering from grade three or below hearing difficulties, equating to 3.6 per cent of the total unit.

Earplugs are issued to all troops, but soldiers complain that when they use them they lose awareness of events around them and cannot hear commands, so they often pull them out. It is only in helicopters that wearing the plugs is supposed to be compulsory.

Angela King, senior audiology specialist at the Royal National Institute for Deaf People, said she understood why soldiers “in the heat and stress” of battle chose not to wear the plugs. She added that the US military is studying ways of using drug therapy to protect inner ear cells from noise damage.

CASE STUDY: ‘I couldn’t wear ear protectors’

Corporal Martin Webster, 33, who served in Iraq with the 1st Battalion Light Infantry (now The Rifles) in 2003 and 2004, has suffered severe deafness in his left ear ever since the ferocious battles with Shia militia gunmen in al-Amarah during that period.

“After one day of fighting it felt like I had my hands over my ears; it was horrendous. I can imagine what it was like for soldiers in the First World War,” he said yesterday at his home in Falmouth, Cornwall.

“I was serving with a mortar unit and I couldn’t wear ear protectors for tactical reasons. I needed to be able to listen to radio messages while I was right next to the mortar tubes,” he said.

“Now we have young soldiers returning from Afghanistan with similar hearing loss.”

Mr Webster, who left the Army last year after a 12-year career when he was told he could never serve with a mortar unit again, assumed that he would receive compensation for his hearing impairment but his application failed.

“I was told that the hearing damage had been caused after I left the Armed Forces and that it was part of getting older,” he said.

Explore Health

• Expert Advice

• Health Features

• Mental Health

• Alternative Medicine

• Child Health

• Health Club