Citizens of Gibraltar could be set to join the London region for next year's elections to the European parliament.

The proposal appears set to emerge as the front runner in an Electoral Commission consultation on how to incorporate the peninsula into a UK region for the 2004 elections.

A ruling by the European Court of Human Rights in 1999 found the British government to be in breach of its legal obligations in failing to allow Gibraltarians to vote or stand in elections to the European parliament.

Ministers have passed legislation paving the way for Gibraltar to be enfranchised, but have not yet reached a final decision on which mainland region it will be merged with.

With fewer than 20,000 voters, Gibraltar is too small to merit its own separate region.

But once given the vote, political parties in Gibraltar will be able to put forward candidates for the European parliament election in June next year.

They will be subject to the same controls that apply to UK parties and candidates.

Electors in Gibraltar will receive the same ballot paper as the rest of the combined region and there will be a single regional Returning Officer.

The move raises the prospect of voters in the chosen UK region being able to cast a vote for parties based in the Rock, and vice versa.

Voters on the Rock could theoretically opt to support the Conservatives, with the party gaining from its opposition to concessions during negotiations with Spain.

In a consultation document published on Thursday, the commission said it favoured incorporation into the London or South West regions, with which Gibraltar has the most in common.

The key issues for Gibraltar have been identified as the financial services industry, the port and maritime industry and the tourism industry. Other issues that may be considered relevant are historical ties and transport and commercial links between Gibraltar and regions of the UK.

Dr Charles Tannock, a London MEP and Conservative foreign affairs spokesman in the European parliament, told ePolitix.com it would "make sense" to add Gibraltar to the capital's constituency.

The largest Gibraltese community lives in London, where the embassy is also located, he said.

"London would be the most obvious place because it has got the financial services which is the mainstay of the Gibraltar economy and Gibraltans come to London for medical treatment," Tannock added.

The Electoral Commission has also indicated that London was a strong contender for the Gibraltar vote.

"Like Gibraltar, the London region has a strong financial services sector. It also has a major port and a significant tourist industry," it said.

"The London region is the focal point for many of Gibraltar's commercial links with the UK. Transport links between Gibraltar and London also provide an obvious connection - links that could facilitate communication between Gibraltarians and their representatives."

But the South West region is also in the running.

"The South West region has a strong tourist industry as well as historical and some ongoing maritime interests. It is the nearest region to Gibraltar, contains distinct sub-regional interests and identities, and arguably shares with Gibraltar a sense of peripherally," according to the commission.

However, the commission stressed that no option was yet ruled out entirely.