The claim: Spain has more to lose in EU trade negotiations with the UK - because of its trade surplus with the UK.

Reality Check verdict: Spain sells more goods and services to the UK than it buys from the UK. It is also the top destination both for visits by UK residents and for UK nationals living abroad.

A clause about Gibraltar in the EU document outlining the negotiating strategy for Brexit has raised the question of sovereignty over the territory.

Over the weekend, former Home Secretary Lord Howard said the prime minister would defend Gibraltar the same way that Margaret Thatcher had protected the Falklands.

But on Monday, Jack Straw, the former home secretary and foreign secretary who held talks in the early 2000s with the Spanish government about sharing Gibraltar's sovereignty, said the idea of conflict with Spain over the territory was absurd.

He told BBC Radio 4's Today Programme that Spain was unlikely to let Gibraltar get in the way of a future EU trade deal with the UK.

"Spain has hugely more invested in their trade and relations with the UK," he said, adding that Spain exports more to the UK than it imports from the UK, which means it has a balance of trade surplus.

The most recent figures broken down by country are from 2015. In that year:

The UK imported £5.1bn more in goods from Spain than it exported to Spain

It also imported £5.1bn more in services from Spain than it exported to Spain, some of which was due to tourism

UK residents made 13 million visits to Spain, spending £6.5bn

Spanish residents made 2.2 million visits to the UK, spending £1bn

But the UK arguably has more to lose than Spain on the issue of nationals living in the other country, because there are many more British nationals living in Spain than there are Spanish nationals living in the UK.

Of an estimated 900,000 British citizens who live in the EU, the largest number of them, by individual country, live in Spain: 308,805. Of those, 101,045 are aged 65 and over.

About 132,000 Spanish nationals live in the UK.

Correction 4 April 2017: An earlier version of this story said that Jack Straw had organised Gibraltar's referendum in 2002. In fact, while he had said that he would hold a referendum over proposals for shared sovereignty, the referendum that took place in 2002 was organised locally to pre-empt his discussions with the Spanish government.

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