Simmonds, competing in the women's S6 category, took the race out hard from the start and went on to dominate her race.

The 15-year-old double Paralympic gold medallist from Walsall grabbed the lead from the first turn and showed her skill to extend it with a powerful back end to her race.

Simmonds touched in 5min 32.45sec to take the gold medal and claim the first world title of her career.

She finished almost 20 seconds ahead of the athlete in second place, Norway's Sarah Louise Rung, who touched in 5:53.68.

Japan's Erika Nara took bronze in 6:32.36.

Simmonds said: "That felt good tonight.

"I wasn't well last week when I raced in Sheffield but I knew that I would pick it up here.

"It was a hard race but I felt really good and I am happy with how that went."

Thomas Young won the first medal of the night in the men’s S8 100m backstroke as he moved up the field to win bronze in a British record time.

Young swam a well timed race and finished in a time of 1:05.80 to win his first World Championship medal.

Gold was won by Australia's Peter Leek in a world record time of 1:03.18 and silver went to Russia's Konstantin Lisenkov, who finished in 1:04.56.

Young said: "That was a tough swim for me.

"I went into the race wanting to get a medal and a personal best and I achieved both.

"I knocked a second off my personal best and I am pretty chuffed with that.

"I did want a heat swim for this event but I just got in for the final and swam hard."

Stephanie Millward (pictured) swam to the bronze medal in the women’s S8 100m butterfly and lowered her personal best and the British record as she reached for the wall.   Millward touched home in a time of 1:09.24 to take the bronze.

The gold went to Spain’s Sarai Gascon Moreni in 1:07.21.

Australia’s Annabelle Williams won the silver in a time of 1:08.78.

Millward said: "That performance wasn't as good as I anticipated and I was quite tired this evening.

"Although it isn’t a bad start to a competition.

"I had a nice race this morning and I was hoping to follow it up this evening but it wasn't there.

"I am hopeful I will have it for the 100m backstroke."

Lars Humer, Britain's head coach, was happy after a successful opening night.

He said: "Overall, it has been a good day for us.

"We had all of our athletes reach finals and some of them were in their secondary events which is promising.

"We have proven today that we can cope with the conditions at this meet.

"There is unpredictable weather, it is a slow meet and the travelling is difficult but everyone has adapted well.

"We have absorbed the conditions and now we know what we are up against we can progress.

"The highlight of the day is Eleanor’s 400m freestyle.

"She had a good time and she had a lead of 25m against a strong field.

"It was also good to see both Steph and Thomas getting personal bests and medals in their races."