Debris sighted off the coast of Australia has been described as a "credible lead" in the hunt for the missing Malaysian Airways plane.
The huge multinational search effort is being focused on the location 1,500 miles (2,414km) from Perth after two large objects were spotted on satellite images.
Britain has tasked survey vessel HMS Echo to help with the operation - but it will not arrive for several days.
Prime Minister David Cameron's spokesman said the Government stood ready to provide any other assistance requested.
"The exact role (HMS Echo) will play will depend on the status and the nature of the investigation by the time it arrives in that area," he said.
"That is currently the assistance that's being provided, but we stay in close touch with the Malaysian authorities and if there's more to do that the British Government can do then we will, of course, look upon that very constructively."
Malaysia Airlines flight MH370 was en route from Kuala Lumpur to Beijing on March 8 when it went out of contact with air traffic controllers.
Malaysian Transport Minister Hishammuddin Hussein cautioned against jumping to conclusions but told a press conference the sighting was a "credible lead".
David Gleave, an aviation safety researcher at Loughborough University, said all delays would make salvage work more difficult.
"Working on the big assumption that it is part of the plane then they need to establish the exact location, which they have done," he said.
"They may then place a buoy with it so they can continue to track it and there will be a navy ship diverted to the search area.
"If it is then identified as part of a plane, they would secure the wreckage so it does not sink with flotation attachments, and the search area around it would be intensified."
Mr Gleave said experts would then be brought in to start mapping the ocean floor and establish how far it could have drifted.
"Each day you could be adding a lot of sea area to the search, because of the ocean currents. And the longer it takes the battery life on the black box is less likely to last," he said.
"Oceanographers will be brought in to estimate how far they expect it to have drifted and a guided search for the plane would begin.
"In searches like that you look for clues on the surface and under the sea you listen for anything that the black box is pinging; however, that may have been disabled.
"If the plane is found, say 12,000ft (3,658m) down, then you need remotely controlled submarines with cameras on board to go to the bottom of the ocean.
"The key will be whether there is any data on the flight recorders. Once they have them on the surface they have to be taken to the relevant organisation to read the data.
"Once it's taken to be read you then have to dry the boxes out, which takes just over a day, and then you can start to access the information."
Britain is offering Malaysian authorities a liaison team f rom the Ministry of Defence to help with planning advice and aviation security s pecialist advisers.
Search and investigative teams also stand ready to help if the crash site is confirmed, the Foreign Office said.
The UK has already sent two Ai r Accidents Investigation Branch (AAIB) representatives while experts from the MoD, the Hydrographic Office, Department for Transport and Met Office are working with Malaysian authorities to analyse satellite, weather and sea data.
A British fishery patrol vessel has been involved in search operations in the waters around the British Indian Ocean Territory and police have also helped with routine checks on the MH370 flight manifest.
A Foreign Office spokesman said: "The UK has remained in close touch with Malaysian authorities since the disappearance of Malaysian Airlines flight MH370 on 8th March.
"The PM called PM Najib Razak on Tuesday to offer any additional support to the AAIB assistance already in place.
"Following that, we have been in close contact with the Malaysians and have offered an additional package of support. We are also in close contact with the Australians and today we have confirmed that HMS Echo is already heading towards the southern Indian Ocean."