In the most recent incident on Friday, a soldier from the 1st Battalion The Royal Anglian Regiment was shot dead and a second injured during a patrol to check on an irrigation project in Jusyalay in Helmand Province, Afghanistan.

The patrol came under fire at 6am local time and an emergency helicopter was dispatched to the area but was unable to save the soldier, who died at the scene. The injuries of the other soldier are not thought to be lifethreatening.

On Thursday, two soldiers from 1st Battalion The Irish Guards were killed and another two seriously injured when a roadside bomb detonated next to their patrol just after midnight local time in southern Iraq.

The soldiers, Lance Corporal Kirk Redpath and Lance Sergeant Chris Casey, were travelling in a convoy north of the Rumaylah oilfields near Basra City.

Redpath was in the lead vehicle on sentry duty and was killed instantly. The 22-year-old was a member of the battalion's intelligence cell, a job which did not require him to leave the army's base although he consistently volunteered to do so.

He was just one week away from returning to his home in Essex, and leaves behind his parents and a younger brother, Grant.

Colleagues described a man who, in addition to his military skills analysing enemy capabilities and tactics, was an "excellent" side drummer in the Pipes Platoon.

"Not only did he bring valuable insights as an intelligence analyst, working hard to get inside the heads of the numerous factions involved in the current conflict in southern Iraq, but he also brightened up the place;

he always had a joke to tell or an anecdote to recount, " said Lieutenant Colonel Michael O'Dwyer, Redpath's commanding officer.

"Only the day before he was so tragically killed he was visiting all the offices in the headquarters, handing out sweets and asking after other people's welfare. He was an outstanding musician and a very professional soldier."

Casey was standing alongside Redpath on a Snatch armoured landrover when the bomb went off and was also killed instantly. The 27-year-old from London had been in the army since 1998 and had served in Kosovo and Northern Ireland, as well as on a previous tour of Iraq during the initial invasion in 2003. He was married with two children.

O'Dwyer said Casey was tipped for promotion following his planned return to England in September, where he was to take up a post as an instructor at an army training centre.

"For much of the time of his tour in southern Iraq he was involved in training the Iraqi army, " he said. "He had hundreds of Iraqi soldiers hanging on his every word. That's not surprising given his passion, enthusiasm and genuine interest in their wellbeing . . . he was a very special talent."

Earlier in the week on Tuesday, Leading Aircraftman Martin Beard, from 1 Squadron, RAF Regiment, died after he was hit by small arms fire during a foot patrol in the AlWaki district of Basra in southern Iraq. He came under attack at 8.30pm local time and was evacuated by helicopter to hospital but did not survive.

Beard, from Nottinghamshire, had just turned 20 and been with the squadron since September. He leaves behind his fiancee and his family, including two sisters.

Squadron Leader Jason Sutton, commander of No 1 Squadron, described Beard as a quiet man who had a "wicked" sense of humour.

"Strong, fit and an exceptionally gifted infantryman, he had such a bright future and had already set his sights on selection for Special Forces, " he said. "I have no doubt whatsoever he would have succeeded in that, as he did in all else."

On Monday, Private Craig Barber of 2nd Battalion The Royal Welsh was killed by a single shot through a crack in the driver's hatch of the Warrior armoured vehicle he was driving through Basra City.

Barber, 20, was hit in the head by a single round and died immediately while his colleagues were forced to abandon their attempts to remove his body and called in a recovery vehicle after they came under more small arms fire.

The soldier from Wales was to return home on leave later this month to celebrate his first wedding anniversary. Barber, who joined The Royal Welsh in 2004 and was on his second tour of Iraq, leaves behind his wife and a three-year-old son.

British forces have suffered 41 fatalities in Iraq so far this year and the latest deaths bring the total number killed there to 168; in Afghanistan, the death toll stands at 69 since the war began in 2001.