The break-in, on September 28, was the third time the pensioner's Ash Court home was targeted by thieves and at Lincoln Crown Court on Friday Shane Cooper (18) was jailed for three years for the latest offence.

The woman, who does not want to be named, caught him red-handed in her bedroom and when confronted he fled through a window with a jewellery box with her wedding ring and a brooch given to her by her husband 50 years ago.

Simon Rowe, prosecuting, said the victim heard knocking on her window and went to her bedroom to investigate. When she tried to open the door she found her way blocked. She gave the door a hard push and found herself face to face with Cooper, who was with a second person who has never been identified.

She raised the alarm and police found stolen property discarded nearby. But the wedding ring was kept by Cooper, who later sold it.

He was arrested after his fingerprints were found at the scene and later admitted breaking into the homes of two other elderly people in Parkside Crescent, Spalding, on the same night and also to burglary at a butcher's.

Cooper, of Clarence Gardens, Spalding, admitted the burglary at Ash Court and asked for three other to be taken into consideration. The court heard he had three previous convictions for breaking into the homes of elderly people.

Mr Rowe said: "There is a significant history of targeting vulnerable elderly victims."

Stephen Clayton, defending, said Cooper had a chaotic upbringing and eventually turned to drugs. He said that since being arrested and remanded in custody Cooper has shown remorse and wants to move on in his life.

Speaking after the hearing the victim said: "It was very scary. He was as shocked as I was.

"My carer said I was taking it well but I was a nervous wreck and I still am.

"The courts are too lenient. He will be out in 12 months but that's the world we live in now. It's a different one to that which I grew up in."

Lincolnshire Police said the result of the trial is "fantastic" for the victim and the community.

A spokesman added that Operation Neptune has been launched to improve security for the elderly in sheltered housing complexes and patrols have been increased to prevent such crimes.