Introduced by the Normans when they invaded back in 1066, rabbits are now a ubiquitous sight in the meadows and fields throughout Britain:
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By the 1950's rabbits reached an estimate population of nearly 100,000,000 and were considered a severe pest for farmers, so myxomatosis was released. Having the desired affect of reducing the rabbit population by 99%.
This massive reduction in the rabbit population had various side affects on other species.
Perhaps not surprising, there was an initial increase in plant variety, but this was eventually replaced by scrub. Some invertebrates - snails, marbled white butterflies and burnet moths benefited from the increased grass, yet others - adonis and large blue butterflies suffered, as well as sand lizards and ground nesting birds through the loss of habitat.
Surprisingly, foxes were not drastically affected, as they changed to catching voles, but this had the side affect of decreasing owl populations who now had less voles to catch.
Other predators of rabbits- stoats and polecats - suffered the largest decline in numbers as did red kites and buzzards
Eventually rabbit populations built up an immunity to myxomatosis (although there are still small outbreaks) and the population has returned to an estimated several million and can be seen dashing into the undergrowth near the Ock:
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Not all rabbits are as quick and as rabbit numbers have increased, so have their predators:
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References:
Collins complete guide to British animals
Mammals of the British isles (Mammal Society)