The world's first test-tube burger, made from lab-grown meat, was today cooked and served in London.

The 5oz (142g) patty, which cost £250,000 to produce, was dished up before an invited audience.

It has received the financial backing of Google founder Sergey Brin, who reportedly put some £215,000 of his vast fortune towards the project.

Scientist-turned-chef Professor Mark Post produced the burger from 20,000 tiny strips of meat grown from cow stem cells.

After trying his own creation for the first time today, he said: "I think it's a very good start, it proved that we can do this, that we can make it and to provide a start to build upon - I am very pleased with it."

Chicago author Josh Schonwald and Austrian food researcher Hanni Rutzler gave the meat's taste a mixed review after becoming the first to try it.

After taking a bite, Ms Rutzler said there was "intense taste" but that she had expected a softer texture.

"It's close to meat, it's not that juicy, but the consistence is perfect," she said.

"The absence is the fat, it's a leanness to it, but the bite feels like a conventional hamburger," Mr Schonwald said.

"This is kind of an unnatural experience in that I can't tell you over the past 20 years how many times I have had a burger without ketchup or onions or jalapenos or bacon."

Prof Post believes the new burger could herald a food revolution, with artificial meat products appearing in supermarkets in as little as 10 years.

In a video shown before the burger was cooked in butter by chef Richard McGeown, Mr Brin said he was backing the technology because it could be "transformative for the world".

He said: "There are basically three things that can happen going forward - one is that we can all become vegetarian. I don't think that's really likely.

"The second is we ignore the issues and that leads to continued environmental harm and the third option is we do something new.

"Some people think this is science fiction - it's not real, it's somewhere out there. I actually think that's a good thing.

"If what you're doing is not seen by some people as science fiction it's probably not transformative enough. It's really just proof of concept right now.

"We're trying to create the first cultured beef hamburger. From there I'm optimistic we can really scale by leaps and bounds."

Today's demonstration was originally planned for October last year, with celebrity chef Heston Blumenthal cooking the burger for a mystery guest.

The raw ingredients which went into creating the burger sound distinctly unappetising - 0.02in (0.5mm) thick strips of pinkish yellow lab-grown tissue.

A multi-step process is used to turn a dish of stem cells into a burger that can be grilled or fried.

First the stem cells are cultivated in a nutrient broth, allowing them to proliferate 30-fold.

Next they are combined with an elastic collagen and attached to Velcro "anchor points" in a culture dish. Between the anchor points, the cells self-organise into chunks of muscle.

Electrical stimulation is then used to make the muscle strips contract and "bulk up" - the laboratory equivalent of working out in a gym.

Finally the thousands of beef strips are minced up, together with 200 pieces of lab-grown animal fat, and moulded into a patty. Around 20,000 meat strands are needed to make one 5oz (142g) burger.

Other non-meat ingredients include salt, egg powder, and breadcrumbs. Red beetroot juice and saffron are added to provide authentic beef colouring.

A major advantage of test-tube meat is that it can be customised for health, for instance by boosting levels of polyunsaturated fats, Prof Post has said.

Manufacturing steaks instead of minced meat presents a much greater technical challenge, requiring some kind of blood vessel system to carry nutrients and oxygen to the centre of the tissue. Making artificial chicken or fish from stem cells might be easier.