With Supreme Court upholding Sanjay Dutt's conviction under the Arms Act for possessing unauthorised arms and declining his plea for probation, the Bollywood film star will now spend three and a half years of his remaining sentence in jail.

The bench of Justice P.Sathasivam and Justice B.S.Chauhan, while upholding Dutt's conviction under the Arms Act, however, reduced his sentence from six years to five years. Dutt has already been in jail for 18 months.

Dutt's hopes for a relief from the apex court were dashed Thursday as it held: "The circumstances and the nature of the offence as analysed and discussed are so serious and we are of the view that they do not warrant A-117 (Sanjay Dutt) the benefit of the provisions of the Probation of Offenders Act."

However, the court said that "taking note of various aspects, we reduce the sentence to minimum period, from 6 years to 5 years."

The court gave Dutt four weeks to surrender for serving the remaining sentence.

"The appellants-accused concerned are directed to surrender within a period of four weeks from today (Thursday) in order to serve the remaining period of sentence. The designated court is directed to take appropriate steps for their custody in case of failure to comply with the above said direction," the court said.

Dutt was convicted for possessing AK-56 rifles, magazines, cartridges, a 9 mm pistol and hand grenades. The weapons and ammunition was allegedly part of the arsenal that was to be used in the Mumbai bomb blasts and was supplied to Sanjay Dutt at his Pali Hill residence by underworld operative Samir Hingora.

However, Hingora got the reprieve as his sentence was reduced to what he has already undergone. While reducing Hingora's sentence, the court dismissed the Maharashtra government's appeal for enhancing sentence.