Those bereaved by the Marchioness riverboat tragedy will attend a memorial service later this month to mark the 25th anniversary of the River Thames disaster which claimed 51 lives, including that of an Ipswich man.

Ipswich Star: Plaque for the 51 victims of the Marchioness disaster. Photo credit: John Stillwell/PA WirePlaque for the 51 victims of the Marchioness disaster. Photo credit: John Stillwell/PA Wire

On August 20 1989 – a hot late-summer evening – the pleasure boat Marchioness, packed with partygoers, collided with the dredger Bowbelle and sank in the Thames in central London.

The names of the dead, including Ipswich man Christopher Garnham, will be read out at the service on Wednesday August 20.

Mr Garnham, 31, was an award-winning photographer and artist.

Other victims included Francesca Dallaglio, 19, the sister of former England rugby captain Lawrence Dallaglio, and merchant banker Antonio de Vasconcellos, whose 26th birthday was being celebrated aboard the Marchioness.

Ipswich Star: The wrecked hull of the Marchioness lying partially submerged in shallow water on the north band of the river Thames. Photo credit: Tony Harris/PA WireThe wrecked hull of the Marchioness lying partially submerged in shallow water on the north band of the river Thames. Photo credit: Tony Harris/PA Wire

The service will be conducted by Southwark Cathedral Dean the Very Rev Andrew Nunn and later two launches will be provided to allow families to drop flowers at the spot on the river where the accident happened.

Those attending the service will include some who have campaigned, through the Marchioness Action Group, for Thames safety improvements following the tragedy.

These same bereaved families had to endure a 10-year wait for the announcement of a public inquiry into the disaster following an earlier 1991 report from the Marine Accident Investigation Branch (MAIB).

That first report said the failure of both vessels to mount a proper look-out was the immediate cause of the tragedy.

This was the same conclusion reached by Lord Justice Clarke when his 2001 report was published after the public inquiry, announced in 1999, was finally held.

While the MAIB report said that there were marine regulation faults going back 25 years, the Clarke report said it was “a catastrophe that should never have happened”.

In the years between the two inquiries the families had had to absorb the news that the Bowbelle captain, Douglas Henderson, had been formally acquitted after juries at two separate trials failed to reach verdicts on a charge of his failing to keep a proper look-out.

The families also had to come to terms with the decision by Westminster Coroner Dr Paul Knapman to cut off the hands of more than 20 of the Marchioness victims for identification purposes – an action criticised in the Clarke report.

The Clarke report was also critical of Captain Henderson, who had drank six pints of lager in the afternoon before the tragedy. There was also criticism of the owners of both vessels.

An inquest jury into the disaster returned a verdict of “unlawful killing”. In July 1996 the Crown Prosecution Service said there was insufficient evidence to justify any further criminal proceedings.

After the Clarke report River Thames rules were tightened, including – in 2002 – the introduction of the first lifeboat services on the Thames.