Spain's foreign minister has suggested that the UK's future relationship with the European Union is linked to resolving Gibraltar's status post-Brexit.
José Manuel Albares made the comments during a BBC interview, raising tensions over the British territory.
Since December 2020, a temporary arrangement has allowed Gibraltar's citizens to remain part of the Schengen border-free area.
However, no permanent solution has been agreed upon.
José Manuel Albares spoke to BBC Newsnight
BBC Newsnight
Spanish officials have repeatedly threatened to close or restrict the border crossing.
The diplomatic standoff comes as Sir Keir Starmer's Government seeks new agreements with Brussels.
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Spanish foreign minister José Manuel Albares told BBC Newsnight: "The relationship between UK and European Union, it's a comprehensive relation, a global relation.
"It is not just pick and choose relation because there are many, many things that we have to talk about. Gibraltar included."
Political editor at Newsnight Nicholas Watt said: "So that means that if there is a much bigger negotiation, Gibraltar would have to be there. Because as far as you're concerned, Gibraltar is not resolved.
He explained: "It's not resolved yet. There is no agreement. And it's very clear it's part of the withdrawal agreement. We need to solve the issue of Gibraltar in order to have a full EU-UK relationship.
Talks are already facing delays due to French demands for fishing rights in UK waters. Spain's position on Gibraltar adds another complication to these negotiations.
The territory's status was settled 312 years ago when the Treaty of Utrecht transferred ownership from Spain to Britain.
Despite this long-standing arrangement, Madrid continues to press its claim.
The issue has gained additional significance following Labour's decision to surrender control of the Chagos Islands last year. This has prompted debate about other British Overseas Territories including the Falklands and Gibraltar.
Keir Starmer is looking for a new EU deal
PABoth territories face long-standing claims from Argentina and Spain respectively. The mountainous three-mile long rock peninsula shares a land border with Spain.
Madrid remains insistent on eventually obtaining total sovereignty over Gibraltar. However, the Rock's 2006 constitution provides significant protection against any change in status.
It stipulates that there can be no transfer of sovereignty to Spain against the wishes of its voters. Gibraltarians have made their position clear in the past.
In a referendum in 2002, they resoundingly rejected the idea of joint sovereignty between the UK and Spain.
