Four people who were snared in a four-month undercover police operation to rid Winchester of heroin dealers had their sentences cut at London's Appeal Court.

But two others were told they would have to stay behind bars for the whole term.

All six were caught after police launched a massive dragnet operation which began in November, 2001, and they were sentenced between January and October last year at Winchester Crown Court.

They were among 24 defendants facing a total of 68 charges arising out of the operation, which involved undercover police posing as drugs buyers to flush the dealers out, the Appeal Court heard.

Ex-soldier, Raymond Derryhouse (40), of Highcliffe, Winchester, who admitted four counts of supplying heroin, lost his appeal against a five-year sentence.

Maria Smith (20), of Orchard Close, Colden Common, Winchester, who received four years after admitting five charges also had her appeal dismissed.

Michael Vincent (20), of Fivefields Road, Highcliffe, Winchester, who admitted seven charges of supplying heroin, had his four-year jail term reduced to three.

Vincent, who suffered from chronic schizophrenia, and was currently being detained in hospital under the Mental Health Act, sat at the back of the court flanked by three psychiatric nurses.

The reduction in his sentence meant he was freed immediately but he will remain in hospital as a voluntary patient.

His mother, Tina Vincent (44), of the same address, who had admitted seven charges of supplying a Class A drug, had her five-year sentence cut to four .

Mr Justice Elias said she seemed to be making a "sea-change" in her life.

Also successful with their appeals were Kelly Bignell (22), of Black Swan Buildings, Southgate Street, Winchester, who had her 30-month term in a young offenders' institution reduced to 21, and Clive Yeo (30), of no fixed abode, whose six-year jail term was reduced to five.