HISTORY will be made on the waters of Portland Harbour today when Britain’s Paralympic sailors bring home the country’s first medals in the sport.

Top performances by the gold-placed Helena Lucas have guaranteed her with at least silver in the 2.4metre keelboat class as she goes into today’s final race.

The Skud-18 duo of Alex Rickham and Niki Birrell have also secured ParalympicsGB a place on the podium but the four-time world champions are determined to give it their all to achieve silver.

Meanwhile there was a shock for Portland’s Sonar team of John Robertson , Hannah Stodel and Steve Thomas who pulled themselves up three places to the bronze spot, one point away from silver – only to have their Paralympic dream all but snatched away.

After an impressive comeback on the penultimate day of the London 2012 regatta, the trio received a protest from the international jury who claimed that the team bosun had wiped the boat's keel despite being asked to stop while the vessel was out of the water being patched up on Tuesday.

A British team spokesman said the work did not provide a performance advantage and they were currently working out how best to appeal.

But for now, the protest has been upheld and the Brits given a four-point discretionary penalty, slipping to fifth position overall – three points away from the bronze spot and and five points away from silver.

Sonar crew Steve Thomas, of Easton , Portland, praised their Dutch rivals Udo Hessels, Marcel van de Veen and Mischa Rossen who have secured gold with a day to spare.

The 35-year-old added: “We’ll keep fighting hard. As we’ve seen, the results today were all over the place, anything can happen.”

With just one final race scheduled to take place in each of the three keelboat classes today from 11am, national attention is expected to turn to Portland Harbour to witness Britain’s first medal since sailing officially became a Paralympic sport 12 years ago.

Lucas, 37, of Fortuneswell , said: “I can’t get too excited yet, there’s still another race to go, gold's not in the bag yet. But it’s a fantastic feeling to know you’ve definitely got a medal.”

There were tears back ashore for Skud-18 World Champions Birrell and Rickham who are now an unassailable eight points behind the gold-placed Australian team of Daniel Fitzgibbon and Liesl Tesch.

They could win silver if they finish two boats ahead of USA team Jen French and JP Creignou in today’s race.

Portland's Birrell, 26, said: “Congratulations to Australia, they sailed a good week and have won the gold I think, congratulations to them.

“We’re a bit disappointed right now but we’ve got bronze in the bag so we'll go to sleep and then fight as hard as we can with the Americans to get silver.”

Helm Rickham, 30, added: “We’re happy to be in for a medal as it stands.

“To be a home Games and to get a medal was our first goal, for it to be gold was the expectation, which I think we deserved to have given our results over the last four years.

“But at the same time, it’s sailing, you can't put expectations on sailing.”