Our man in Afghanistan: John Scott's latest report from the war-torn country

Here is the latest in a week-long series of reports:

The British Army has hit a near £500,000-a-year bullseye selling unwanted ammunition in Afghanistan, it was revealed today.

It is earning £40,000 a week by destroying degraded bullets that are passed their sell-by date.

The ammunition – ranging from 50 caliber machine gun shells to 9mm pistol rounds – is being turned into brass and scrap metal that sells for £2,000 a ton. The bullets are fed into a kiln that 'cooks' them until the round goes off harmlessly inside the incinerator which, appropriately, is known as the pop corn machine.

At the moment it is producing 20 tons of brass salvage and scrap metal a week while between January 2012 and the end of last year 1,000 tons of ammo was destroyed in the machine. Larger munitions are removed by controlled explosion while rockets are returned to the UK. Danish tanks – the only ones in Afghanistan – are employed to crush empty fire extinguishers that could be used in the making of Improvised Explosive Devices(IED). They just drive over them.

Vehicles used by frontline army units, such as the giant Mastiff armoured troop carrier, are painstakingly cleaned and Bio washed to get rid of potentially harmful dust and bugs before being moved back to Britain by boat or plane.

This joyless work is carried out at Camp Bastion by the troops who drove them as their final chore before finishing a tour of duty. A Land Rover takes a back-breaking 22 hours of washing and brushing before it passes the cleanliness test because it has a hollow chassis.

Almost 3,500 vehicle will have been returned from Afghanistan by the end of the year with each being in tip top condition ready to be used in other military operations.

Pete Beaumont, from the Defence Support Group who conduct the final check before giving the all clear for a vehicle to be returned to UK, commented: "The system is working really well although we are trying to streamline the repair process. The army has been in Afghanistan for 12 years and it is vital that it leaves in good order."

Lt Col Richard Gibb, is head of the 200-strong Theatre Support Group that ensures every vehicle and large piece of equipment is properly maintained before being moved back to Britain. He explained: "It is far more efficient to do it this way that to find somebody to carry out the work after getting back to the UK."

As a result mechanics are working so hard they are returning home after four instead of eight months in Afghanistan. Despite that mountain of work, £30 million worth of spares have already been returned because the number of trucks and fighting vehicles actually being used on the ground is constantly being reduced.

The redeployment phase of the operation has put the spotlight on some of the less high profile roles in the military, such as the Close Support Logistic Regiment who have hundreds of people currently serving in Afghanistan. They organise and drive the convoys of up to 50 vehicles at a time that cross the desert to supply frontline forward operating bases(FOBs) with water, rations and other equipment before returning to Camp Bastion with unwanted kit. As the number of FOBs reduces with the draw down of troops, insurgents are looking for fresh targets, increasing the level of danger to the convoys during journeys that can take 12 hours to complete.

Major James Brown, from the unit, said: "There is obviously a threat to them, the main one being from IEDs. The most dangerous are car bombs but we are also encountering 'pillow' explosives that look like an air bed and are just left lying on the road surface. We just have to keep on trucking because the more you move, the harder you are to hit."

Giant tank transporters are included in their fleet of vehicles and one of these was recently used in a top secret operation to recover an Apache attacker helicopter forced to make an emergency landing in the desert after being hit by technical problems during a mission.

Mechanics also face fresh challenges. They have been repairing and giving MoTs to up to the vehicles being used by the military throughout the conflict but now also have to inspect and fix all those being returned to the UK.

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Sgt Matthew Price, a 26-year-old father of two who met wife Lee while on deployment in the Falkland Island and is now in charge of a team of mechanics at Camp Bastion, explained: "We work on 200 different types of vehicles ranging from Warriors to Land Rovers and we have just been asked to fix the cookhouse gas cookers as well. My team is working on 20 vehicles at the moment and are putting in 13 hour days, seven days a week. It is hard for all of us.

"The vehicles being returned from the FOBs are arriving in pretty bad condition and need a lot doing to bring them up to scratch. The problem is that they have been out there for two or three years at bases that do not have the same facilities as we have here and have just had to make do the best they could. We bring them all up to UK road worthy standards before they are flown home."

Five workaholic metal smiths from the group – all from the Royal Electrical and Mechanical Engineers(REME) – have still found time to make a seven foot high metal statute of a desert rat, the emblem and moniker of the 7th Armoured Brigade, that gives its name to the battle group now operating in Helmand. The rat, painted in its traditional red colour, will have pride of place at the Brigade's HQ in Hohne, Germany, and stands as a lasting testimony to the current campaign.

The unit also packs up much of kit that is being flown home, ranging from weapons and helicopter blades to uniforms and clothing. It is his 10th, and last, operational tour. He explained: "I am not getting any younger and it is time to leave it to the young 'uns."

People like Private Teresa Moloney, aged 19, from Kingstanding, Birmingham, who is also member of 237 Squadron said: "My mum Suzanne misses me a lot and I love her very much, but I have not had the time to miss her because I have been so busy. I only joined the Territorial Army in 2012 but signed on for this tour as soon as I could because I knew British troops were being withdrawn this year and did not want to miss out. I am really enjoying it."

Private Debbie Leja, aged 29, an ex-pupil of St Edmunds, Compton, and from Codsall joined the Territorial Army three years ago. She works with adults with learning difficulties. She said: "I was in the regular army for a year and as soon as I left I regretted it. This is my first operational tour and a great opportunity to put training into practice."

Private Daniel Morgan, 25-year-old electrician from Coseley, another from 237, added: "It all comes at once and so you are running around like a madman but the times goes quickly."

TOMORROW: In John Scott's final report from Afghanistan, read all about the most bizarre car boot sale in the world