Professor Chandra Wickramasinghe said the globule from the rock named Tissint is rich in carbon and oxygen and insisted they could only have been produced by living organisms.
He added that they could not have been caused by contamination when they fell to Earth.
Prof Wickramasinghe, 72 â€” famous for controversial ideas such as that the flu virus and even life itself was brought to our planet by comets â€” said: “It is impossible to understand how carbon-rich particles of such uniform sizes and shapes got inside a rocky matrix if they are not relics of some algal species.
“Tissint was collected weeks after it fell, and terrestrial contamination seems unlikely. In any case the structures we found were on newly fractured surfaces, from the interior of the meteorite.”
The meteorite was named after the village where it came down in the Sahara desert in Morocco last July.
It was probably blasted from Mars when it was hit by an asteroid millions of years ago.
A piece of it was examined at the Buckingham Centre for Astrobiology and Cardiff University.
PhD student Jamie Wallis, who was working with Dr Wickramasinghe, said: “All the indications are that structures such as we have found are evidence of life on Mars.
â€œThe spheres are probably remnants of polysaccharide shells surrounding algal type cells.”
In 2009, a NASA team claimed they had photographed Martian organisms inside another meteorite that is kept in London’s Natural History Museum.
Their electron microscope showed a bumpy surface resembling a fossilised colony of microbacteria in a rock that fell from the sky in Nakhla, Egypt, in 1911.
The team from NASA’s Johnson Space Centre examined the space rock to support their claims in 1996 that Martian bugs had been found in a meteorite, ALH84001, found in Antarctica where it had been lying for thousands of years.
That discovery, which NASA later officially backtracked from, was considered so important that President Clinton addressed the nation on TV.
Earlier this month, another group of scientists claimed that the first two Viking probes that NASA landed on Mars in 1976 discovered life but failed to recognise it.