Updated

Irate drivers waited in sweltering, hours-long queues to enter Gibraltar on Tuesday as Spain enforced tight border checks in a growing row with Britain over the tiny territory and its surrounding waters.

On the "Rock" itself, defiant residents declared themselves thoroughly British, surrounded by English pubs serving fish and chips, Royal Mail letter boxes, bright red telephone cabins and the occasional monkey.

Gibraltarians are firmly on London's side in the latest of a long string of spats with Madrid over the fate of the British outpost which lies off the southern tip of Spain and within sight of the African coastline.

The latest flare-up was sparked when Gibraltar sank concrete blocks in disputed waters to create an artificial reef, making it impossible for Spanish fishing fleets to operate in the area.

"We don't want to belong to Spain, we are happy being British," said 42-year-old Gilbratarian Kim Bickerstaff, complaining that the Spanish border checks hurt residents and visiting workers.

Indeed, life on Gibraltar, ceded by Spain to Britain in 1713 under the Treaty of Utrecht, looks British right down to the police officers with their tall helmets.

A rare exception is the monkeys who wander nonchalantly through the streets. They live in the forests of the rock that looms over Gibraltar and descend during the day when tourists are about. Feeding the animals is forbidden.

On a pub terrace, 52-year-old office worker Rosana sat with her family and slipped easily between English and a Spanish typical of the neighbouring southern region of Andalusia.

"At home we speak both languages because we are 'llanitos'," she said, as people of Gibraltarian origin are known.

"We are British," she added proudly.

Rosana said she backed Gibraltar's creation of an artificial reef and could not understand the response of Spanish Prime Minister Mariano Rajoy's conservative government, which affected not only Gibraltarian residents but also workers coming from the Spanish border town of La Linea.

"They don't know what is happening and they are creating all kinds of obstacles," she said.

Some 10,000 Spaniards work in Gibraltar and about 6,000 Gibraltarians live on the Spanish side where housing in cheaper, according to Madrid.

"Those of us who have family or work here have a different viewpoint from the rest of the Spanish, we are not anti-Gibraltarian," said Rafael Marquina, a 46-year-old government worker from La Linea who was visiting his aunt.

"All the problems come from an incorrect starting point: that Gibraltar is Spanish. But Gibraltar is British and its people feel British," he said.

"The day they accept that it is in fact English they will be able to solve any problem and reach agreements."

In the meantime, however, the line of cars trying to enter the territory of just 6.8 square kilometres (2.6 square miles) and home to about 30,000 people, grew to several kilometres.

By early afternoon, the Royal Gibraltar Police said waiting times had stretched to about five hours for drivers trying to enter the rocky outpost, overlooking the only entrance to the Mediterranean from the Atlantic Ocean.

"This has happened to me several times, at least six or seven times" in recent days, said Francis Perez, a 30-year-old unemployed construction worker as he waited to cross the border into Gibraltar with his family.

Perez is from Madina Cidonia, a Spanish city located about 50 kilometres (30 miles) from Gibraltar, and like many area residents he heads to the British outpost to buy fuel for his car and tobacco because taxes there are lower.

"It's horrible to have to spend hours to get in and out of Gibraltar. Today it's not too hot but there are other days when it was unbearable. It's all just politics," he said, as his car crept ahead.