Bernard Hegarty was a bright young man with a brilliant future.

After graduating from the University of Brighton, he went on to become an architect and was building up a successful career in London.

But the 29-year-old's dreams were cut short last week when he was stabbed to death in an unprovoked attack.

Bernard was shopping for carpets for his new home in Tottenham, north London, when he was stabbed in the chest as he walked back to his office.

He was flown to the Royal London Hospital, Whitechapel, where his large Irish family kept a bedside vigil until he died on Monday.

Yesterday his devastated relatives told how Bernard's death had torn out the heart of their family.

Making a tearful plea for witnesses to his murder, his brothers Matthew and Michael said the graduate did not have an enemy in the world.

Matthew, 26, who works in the City, said: "Bernard was a well-loved, caring and strong man who formed a central part in our very close, loving family. We miss him terribly.

"The heart of our family has been torn out and we are struggling to understand how someone can be attacked while carrying out his everyday life."

Michael, 31, a butcher, said: "He was not just a brother. He was my best friend and I could tell him everything."

Asked what he thought of the attacker, Michael said: "What can you say? He tried to rob my brother but he has robbed us and he has torn us apart.

"If you have got any conscience, do the right thing and if you know anything, do the right thing.

"He must be some sort of person to do something like this at 2pm."

The senior investigating officer in the case, Detective Chief Inspector Jim Condron of the Specialist Crime Directorate, said the attacker might have fled empty-handed.

He said: "We have no indication that property was taken. We have reason to believe that the motive was robbery.

"The victim in this case is every mother's son. There are no drugs or a hidden agenda and there is no major or minor scandal attached to this.

"He was an ordinary lad, a professional man who had girlfriends.

"He was just an ordinary person who was enjoying life to the full. On one day while he was in hospital 65 people came to visit him - that is just a sign of how very well liked he was."

Police and relatives want witnesses to come forward and help catch the attacker, who is described as a dark-skinned man.

They point out that the attack took place on a hot day on a busy street and near three pubs so someone must have seen something.

Michael said his brother was street-wise but was not the sort to go looking for trouble.

He said: "He knew how it worked. He would have fancied his chances one on one. This is something he did not see coming.

"Bernard fought in the hospital as much as he could but it was a fight he could not win."

Mr Condron said Bernard was not the sort of man who carried much cash. He had used his credit card that morning to take out a small amount.

Bernard had been looking forward to being best man for a close friend.

Mr Condron urged anyone with information to call police on 020 8345 3775 or Crimestoppers on 0800 555111.