It was a wartime raid which wrecked part of a cannery plant in a coastal town, killing three people as it caused extensive damage.

For more than 70 years the bombing raid was thought to have been the work of the German Luftwaffe.

But now recent research by a Suffolk historian has led to the discovery that the bombs which hit the CWS (Co-op) cannery factory in Waveney Drive, Lowestoft on November 29 1940, were in fact of Italian origin.

Aviation historian Bob Collis, of Oulton Broad, said he made the connection with the Italian Air Force, the Regia Aeronautica, through comparing the records of the Corpo Aero Italiano - the group assigned to attack Britain from bases in Nazi-occupied Belgium in 1940 - and records of bombing raids in Britain from UK archives.

Mr Collis said: "This is another one of those obscure but possibly unique events in Lowestoft's wartime history.

"Ten Italian Fiat BR.20 bombers took off from Melsbroeck in Belgium on November 29, 1940 intending to carry out night attacks on Great Yarmouth, Ipswich and Lowestoft.

"There were no bombs in Yarmouth or Ipswich that night, but at 6.39pm, while air-raid measure 'purple' was still in place and before any alert had been sounded, an aircraft flying at 5,000 feet dropped six bombs on and near the Co-op Society's No.1 Canning Factory in Lowestoft.

"Two of the bombs landed on a concrete floor but the most serious damage and casualties came from a bomb which hit an upright girder in the roof, sending a deadly hail of shrapnel into the plant below which left three people fatally injured and seriously injured several more.

"There was extensive damage to buildings, machinery and preserved food stored there.

"Eight houses in Waveney Drive were also slightly damaged.

"One bomb from the same aircraft cratered a field at Mutford, causing minor damage."

Mr Collis said that ARP and police records made reference to the blast properties of the bombs dropped that night, which were "an unusual100 kg size" - a size never used by the Luftwaffe.

He added: "Several photographs of the damage are in Lowestoft photographer, the late Ford Jenkins' book, 'Port War'.

"Local legend has it that the casualties could have been much worse had more people been present working overtime, but there was none that day and only 14 members of staff were on site when the bombs fell."

Mr Collis said that after having extensive correspondence with Italian historian Luca Guglielmetti, the author of a book on the Corpo Aero Italiano, his information confirmed Lowestoft was bombed by one of the aircraft from unit 13 Stormo's 3 Squadriglia.

The names of the staff who died are recorded on the CWS memorial board.

Mr Collis said: "The raid however, ended badly for the Italians.

"One of the Fiat BR.20 bombers involved crashed into farm buildings while coming in to land at its Belgian base and all six crew were killed.

"Having examined all the evidence it does seem highly likely that the victims of the raid at the CWS in Lowestoft that night were the only casualties of Mussolini's Air Force in Suffolk, and possibly even in the UK.

"By an ironic twist, Italian prisoners of war were employed at the same CWS factory packing trays in 1943."

Mr Collis added that the details of all the local civilian air raid casualties were contained in archives at Lowestoft Record Office, now earmarked for removal to 'The Hold' in Ipswich.

He said: "Suffolk County Council are still going ahead with the plan to remove our unique local archives, despite the public and a host of heritage groups, authors, historians and campaigners sending them a very clear message that they do not want them moved."