Chris Greenwood and Matt Williams

A gunman wrote a tender message to his wife while besieged in his home by police marksmen, it was claimed last night.

Barrister Mark Saunders, 32, was found dead after exchanging fire with police during a five-hour stand-off at his Chelsea flat.

Neighbour Jane Winkworth said he threw a white box from a window as he held police off with a shotgun.

She said the box carried a message written in black pen. It read: "I love my wife dearly xxx."

Witnesses described how a woman, believed to be Mr Saunders's wife Elizabeth, fled the flat in tears shortly before shots rang out last night.

Mrs Winkworth ran for her life after Mr Saunders shot at her as she stood in her back garden.

The businesswoman was then trapped in her basement flat with armed police as they attempted to negotiate the gunman's surrender.

She said the gunman appeared calm and composed, only shouting "I can't hear you" at officers as they tried to give him instructions.

Colleagues at QEB Chambers, where Mr Saunders worked as a divorce barrister, described the incident as a "personal tragedy".

His wife, who uses the professional name Elizabeth Clarke, is a family law barrister at the same firm.

Mr Saunders was a member of the Territorial Army's Honourable Artillery Company for three years until 2002, military sources said. Investigators confirmed a legally registered shotgun kept at his home has been recovered by police.

His father Rodney Saunders, 64, said the shoot-out was an "absolute mystery" and described his son and his wife as an "ideal couple".

Mr Saunders told a newspaper: "It is an absolute mystery. In some ways it would help if we could find out what went on and why he has done it. We are not aware of anything in his work life or private life which might have made him react like this."

Mr Saunders was found dead by members of Scotland Yard's elite CO19 specialist firearms unit at his Georgian terraced flat after a dramatic stand-off.

Neighbour Mrs Winkworth said he fired a shotgun at her as she stood in her garden at about 5pm on Tuesday.

The businesswoman said she ran inside and dialled 999 as Mr Saunders apparently took random shots at surrounding buildings.

Leslie Hummel, whose home backs on to the scene, described how she looked on in horror as the gunman blew out one of his own windows.

He then aimed a shotgun round at one of the first police officers to arrive as he stood inside her home. Mrs Hummel said the officer grabbed his sidearm and returned fire, as Mr Saunders ducked inside his property.

She said one of her daughters' bedroom windows was peppered with shotgun pellets.

Shop workers and customers in nearby Kings Road locked themselves in as armed police filled the streets.

Marksmen also forced their way into surrounding properties as they took up vantage points.

More shots were exchanged between the gunman and police at about 9.10pm before the final fatal confrontation at 9.30pm.

Witnesses reported seeing green flashes, suggesting police may have used stun grenades before entering the flat.

Emergency medical staff were ushered into the cordoned-off area where the gunman was fatally wounded.

Metropolitan Police Commander Ali Dizaei said the gunman made no demands during the stand-off.

The Independent Police Complaints Committee (IPCC) has launched an investigation into the shooting.

A post-mortem examination was taking place yesterday, after which the man's identity will be formally confirmed.

Mr Saunders was educated privately at Kings School, Macclesfield, and then studied law at Christ Church College, Oxford.

A spokeswoman at QEB Chambers, in the capital's Temple area, said colleagues were left stunned at news of the shoot-out.

She said: "He was a very valued member of the chambers and obviously we are shocked and horrified by what has happened.

"We have no knowledge of the circumstances leading up to it and our thoughts are with his family."

Speaking outside her Cheshire home yesterday, Mr Saunders's mother, Rosemary Saunders, 62, said: "It has been a very bad day.

"We're still trying to come to terms with it. We've been told not to talk to anyone."