A special event recreating wartime in Londonderry has taken place to commemorate the city's role in the Battle of the Atlantic.

The naval base in the city – shared by the Royal Navy, the Royal Canadian Navy and the United States Navy – was pivotal to winning the longest continuous military campaign of World War Two.

At one time, 140 Allied escort ships, vital to the protection of convoys in the Atlantic, were based on the River Foyle and in May 1945 eight German U-boats surrendered close to the city.

A recreation of the German surrender took place place at Ebrington Square on Saturday, where a number of wartime museum collections have been on display over recent days.

"Derry is a city steeped in history and often we forget its strategic importance during World War II, although in terms of global significance it played a huge role," the city's mayor Lilian Seenoi Barr told BBC News NI.

What was the Battle of the Atlantic?

The Battle of the Atlantic was fought for control of vital supply routes, beginning as war broke out in 1939.

German submarines were the Allies' principal threat at sea. Winston Churchill once wrote: "The only thing that really frightened me during the war was the U-boat peril."

Skirmishes in the Atlantic continued until the war ended in 1945, but the Allies sank particularly large numbers of U-boats in May 1943, effectively winning the Battle of the Atlantic.

Thousands of merchant ships and tens of thousands of lives were lost during the longest continuous military campaign during World War Two.

More than 66,000 Allied merchant seamen, sailors and airmen died, with 175 Allied warships and 5,000 merchant ships destroyed by German U-boats.

Derry is acknowledged as the Allies' most important escort base during the Battle of the Atlantic.

On 14 May 1945 the first of the U-boats berthed at Lisahally, the naval port on the city's outskirts, were formally ordered to surrender by Admiral Sir Max Horton.

The mayor said as well as holding such vital strategic importance during the Atlantic campaign, the city was also changed by the influx of north American service personnel, housed at Base One Europe, the US Navy's operating base in Northern Ireland.

"The billeting of Allied servicemen here during that time also had a major cultural influence here in the city, where people mingled with the US and Canadian forces," she said.

Derry City and Strabane District Council's head of culture said Saturday's event will give people a sense of the historic significance of events in the city in 1945.

Ex-Wolves and England footballer Geoff Thomas is riding in his seventh Tour De France this summer to raise money towards clinical leukaemia trials.

The retired player and former leukaemia sufferer will be part of a team to cycle the full 2,200-mile (3,540km) route across 21 days in June and July.

The challenge aims to raise £1m for Cure Leukaemia, with Thomas describing it as the "most gruelling" of his life.

He said: "I first did it in 2005, when I was six months in remission – if I could do it then, what's stopping me now?"

Thomas, who lives in Worcestershire, received nine caps for the national team, but was diagnosed with acute myeloid leukaemia in 2003, a year after he retired.

He subsequently raised millions of pounds for charity, became a patron of Cure Leukaemia and launched his own charity, The Geoff Thomas Foundation.

He said if he could reach the finishing line in Paris in July, setting off a week before the pro riders, it would "eclipse anything" he had ever done on a football pitch.

"I don't really think you can do enough training – it's about getting as many miles in your legs as possible, without fatiguing yourself," he said.

"I'm just aiming to do the first day, knowing that you've got over 100 miles to do – you've got to survive that, and then take each day as it comes."

He described reaching Paris on previous tours as "one of the most enjoyable experiences you can have".

"It eclipses anything I ever did on a football pitch, and I was lucky enough to be involved in some great games – it's just a magical time."

Thomas announced his decision to take part in the event at Worcestershire Royal Hospital, where he met current leukaemia patient Adam Claxton, 42, from Worcester.

Mr Claxton said his own diagnosis the previous year had been "a complete shock".

"I'm a football fan, and I remember Geoff as a player – his career was terrific, he had a great run on the pitch and to meet him off the pitch is an honour," he said.

"What he's doing is inspirational."

Dr Salim Shafeek, a consultant haematologist who previously treated Thomas at Worcestershire Royal, said he was "a real ambassador for people with leukaemia".

"It's unbelievable what he's been doing for clinical research over the last 20 years," he added.