Pete Doherty is set to be released early from prison after serving only a third of his sentence.

The Babyshambles frontman is due to be freed on Tuesday, just 29 days into his 14-week jail term.

He was jailed after defying orders to take drug tests during a suspended sentence for heroin possession.

Shortly after starting his stint at Wormwood Scrubs, photographs of the singer, 29, appeared in a national newspaper amid rumours that heroin was being smuggled into his cell at the detox wing. But he is still expected to be released next week, after his sentence was halved and a further 18 days were deducted as part of a scheme introduced last summer to ease jail overcrowding.

He will get a further two days off because of time spent in police custody. He told friends that he plans to "get smashed" by throwing a huge party to celebrate his release.

A source close to the star revealed: "He's planning to go straight to play a gig - and then get smashed. He wants no business appointments for three days so he can really go for it."

Last night, ex-Home Office minister Ann Widdecombe said: "Nobody should ever come out that early." But his release will come as a relief for the organisers of the Glastonbury Festival, who had been hoping he would be out in time for the event in June.

Doherty had to cancel two gigs because of his sentence - a solo show at the Royal Albert Hall on 26 April and an appearance at Love Music Hate Racism the following night.

Emily Eavis, daughter of Glastonbury founder Michael, said she was confident Doherty would perform at the festival, even if the dates had originally coincided with his 12th week in prison. She said: "It's going to be the big comeback show!"

Babyshambles bassist Drew McConnell said: "He's champing at the bit to play festivals, to strap his guitar on again and be the frontman in Babyshambles."