It wasn’t quite the serpentine invasion Samuel L. Jackson had to deal with on a commercial airliner in Snakes on a Plane, but Spanish police were taking no chances.

Eight dangerous snakes were curled up in a Madrid flat yesterday as Civil Guard officers and zookeepers refused to storm the building until the relevant antidote had been administered — or the creatures surrendered.

It could be a long wait: there was no sign of capitulation last night and the antidote could take three weeks to arrive from Mexico.

As the siege dragged on, nervous neighbours in the suburb of Barajas were keeping a close watch just in case the two pythons, five boa constrictors and a rattlesnake slipped out and slithered under their doors.

It was thought that all the snakes were held securely in cages but in case any of them was free — and hungry — the police were staying well away.

The alarm was raised after the serpents’ owner was bitten on the hand by the rattlesnake. Named only by police as Juan C. M., he was rushed to hospital in a serious condition on Friday last week, but released two days later.

He had bought the snakes on the internet.

Doctors had to appeal to hospitals and zoos across Spain for the antidote to treat the rattlesnake bite. However, zoos and hospitals do not keep antidotes for snakes that are not native to Spain.

The Civil Guard’s environmental protection unit refused to let the owner remove the snakes until an antidote arrived. It said that the snakes had been well cared for, but Spanish law prohibited them from being held outside authorised establishments.

Each dose of snake venom antidote costs up to ¤200 (£175), and some prolonged treatment can be costly, said Cesar Olmos, an expert in snake bites.

In remarks not calculated to reassure the waiting police — or anyone in the neighbourhood who has seen the fim Snakes on a Plane, in which Jackson fends off dozens of aggressive fanged nightmares — he said: “These animals are dangerous and can devour a baby or asphyxiate adults.”

Juan C. M. could face prosecution for possession of dangerous reptiles.

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