Ill-fated nuclear sub has taken last dive

Britain's unluckiest nuclear submarine, HMS Renown, is due to be decommissioned tomorrow after 27 disastrous years in which she collided with other vessels, leaked radiation and had one pounds 155m refit which took five years instead of two.

Renown is the third of the four Polaris submarines to be scrapped as they are replaced by the new Vanguard class, carrying Trident missiles. It will sail from Faslane on the Clyde to Rosyth on the Forth.

However, no decision has been taken on the disposal of the hull, and it will join its sister submarines, Revenge and Resolution, at Rosyth. The Navy wanted to fill the vessels with concrete and sink them in the Atlantic, but are not allowed to.

The problem of disposing of Renown will be the last in a series which began shortly after it entered service in 1968. In 1969 it collided with the Moyle, an Irish cattle boat, while surfacing in the Mull of Kintyre.

In April 1974 it hit the seabed during trials following a refit. The captain was court- martialled for "failing to make use of soundings to assist navigation when submerged in confined waters".

Following a problem with its second refit in 1980, radiation leaks were discovered in October 1987 during its third refit. A year later a sailor was overcome by smoke.

The third refit, due to take two years, took five. In January 1990, cracks were found in the reactor of a nuclear-powered torpedo-firing submarine, Warspite, causing Renown's refit to be extended.

The five-year refit failed to correct all Renown's problems and she was only operational for a further 18 months. During a 65-day patrol in 1994, there was a scare over radiation leaks and some of the crew were given potassium iodate tablets. She returned from her last patrol on 16 June 1994. The MoD announced last November that Renown was no longer needed.