Romero, a former rower who won a silver medal in Athens four years ago as a member of the quadruple sculls, was clearly emotional afterwards.

 

She said: "I can't explain it.

 

"It's not the reaction I'd imagined [to winning gold] but it's magical.

 

"I'd have been absolutely crushed if I got the silver.

 

"It's been so hard, I can't explain what I had to go through.

 

"I totally believe in myself now - I did before, but that was the ultimate, facing demons and up against top opposition today.

 

"I knew it was in me - a week ago it wasn't.

 

"Gold medals don't come easy, that's for sure." 

 

Romero joins a very elite group of athletes to have won medals in different sports.

 

Roswitha Krause, of the former East Germany, won a swimming silver at the 1968 Games in Mexico from the women's 4x100 metres relay.

 

She then won silver in the women's handball final at the 1976 Games in Montreal, and won handball bronze at Moscow in 1980.

 

Another athlete, American Tim Shaw, won a swimming silver medal in Montreal in 1976 and a water polo silver in Los Angeles eight years later.

 

Romero, a 28-year-old from Surrey was over three seconds quicker than 33-year-old Houvenaghel, who was seeking to become the first Olympic gold medallist from Northern Ireland since Dame Mary Peters won the pentathlon in Munich in 1972.

 

She had given up a career as a dentist in the Royal Air Force to pursue her dream of winning an Olympic medal.

 

Formerly an cross country runner, she discovered a talent for time-trialling in 2002 not long after she had run the London Marathon for the first time in April of that year.

 

Although being pushed into road time-trialling by her cycling enthusiast husband, she was inspired to take up track cycling after she saw Britain's Chris Hoy win gold in the kilometre at Athens in 2004.

 

Romero's win, five months after her maiden world title in Manchester, means Britain's track cyclists have now claimed an impressive four gold medals from five of what will utlimately be a total of 10 finals.

 

British riders have also now won eight of the 15 medals up for grabs so far.

 

They will be ensured of another one tomorrow after the men's team pursuit of Ed Clancy, Paul Manning, Geraint Thomas and Bradley Wiggins qualifed for the final by setting a new world record.

 

They will meet Denmark in a repeat of the final at the World Championships in Manchester.