“They’re some kind of containers. There’s gas and something else... something alive!”

With a breathless pace that the first film lacked, Quatermass 2 is that rarest of things, a sequel that improves on the original. Before the credits have even started, a woman rushing to get her husband to hospital nearly crashes her car into another driven by Professor Quatermass. The man has been struck by a meteorite - and there's more coming down...

Quatermass is unhappy anyway, his rocket project is in financial trouble and it doesn't look like he's going to get his colony on the moon. Meanwhile, his team are more bothered about the "meteorites", which, it soon becomes clear, aren't meteorites at all but some kind of symmetrical, hollow objects.

With his friend Marsh, Quatermass drives to where the pods have been coming down - a place called Winnington Flats. Spookily, all the roads are empty and they soon find a rival government project cut off from everywhere else, which looks strikingly similar to Quatermass’s own aborted moon project. Unseen, shadowy figures are watching them...

Marsh finds an unbroken pod, which promptly explodes in his face. Quatermass has the chance to spot a mark on his friend's cheek before soldiers arrive, drag Marsh off and club Quatermass to the ground, telling him: "Go... go now..."

Driving to a nearby "new town" populated by people who work for the Winnington Flats complex, Quatermass gets short shrift from the locals, not surprising really, considering he's a scruffy-looking mad bloke who looks like he's just been in a fight and is spouting gibberish.

"The whole area's littered with them. They look like meteorites, but they're not - they're some kind of containers. There's gas and something else... something alive!"

Driving back into London, Quatermass spots lorries carrying technical equipment - it appears that this project/conspiracy is huge, and not particularly secret. It's not long before he's been put in touch with an MP (Broadhead) who's fighting for a public inquiry into the complex, which is officially called a synthetic food factory. Other MPs have been to look round, but when they come out, they don't want to talk about it...

Quatermass and Broadhead manage to wangle places on the next official tour round the complex, but, unseen by them, there's something wrong with the arm of the man who organises it for them...

As they look around the factory (spooky, despite being bathed in sunlight), workers whistle at the woman in the party. "Nothing abnormal in that," Broadhead remarks, and it's not long before the pair of troublemakers wander off on their own.

The film's first really horrific image (and it is horrific, even now) occurs when Broadhead, separated from Quatermass and the rest of the group, is SUDDENLY seen staggering out of one of the huge tanks that dominate the factory, covered in something.

This being a black-and-white film, the audience is initially unsure what has happened to the hapless man - is it his own steaming blood he's covered in, or his burned flesh? It's actually the "synthetic food" (Pot Noodle?) and it burns him to death in front of Quatermass, who then has to make his escape from machine gun-toting guards (fantastic stuff).

As Quatermass attempts to get to the source of the conspiracy, it becomes apparent that whatever it is goes right to the top of government and also concerns a spaceship in orbit on "the dark side of the earth". His only hope is Inspector Lomax (from the first film, although not this time played by Jack Warner) and a permanently drunk journalist (Carry On star Sid James, in his only true horror film role).

As hundreds more pods start raining down and the guards' strong-arm tactics (they are known as "zombies" by the still-normal residents) become too much for the townsfolk, Quatermass 2 is set for an explosive climax.

There are some truly brutal and horrific ideas at work in the film - at one point men's bodies are "pulped" and shoved into a pipeline to stop gas from flowing, Sid James' exit is unexpected and nasty, and people get shot and run over with abandon. There are also echoes of things to come - the villagers approach the complex in much the same way that thousands would in later Draculas and Frankensteins, and versions of the exploding "pods" (there's a fantastic scene when a girl refuses to put one down) can be seen in the Alien films.

Quatermass 2 is brilliantly tense and surprisingly violent, standing as a testament to what Hammer could achieve from the very outset of their horror film glory days. With death and destruction on a grand scale, and a healthy dose of paranoia about authority, the only thing that lets it down is the final appearance of the monsters.