I HAVE been reading a book that describes one of Britain’s biggest rivers, the River Bytham. Never heard of it? Neither had I.

The book is about life in Britain over the last million years and, during that period, the climate has changed regularly and significantly.

There were interglacial periods, where the temperature was generally warmer than today, and cold periods where ice often covered much of Britain.

This variation generally occurred every 50,000 years or so. During interglacial periods, African animals were prevalent in Britain, including hyena, lions and elephants.

As the climate varied, sea level changed, water being locked up on land in cold periods as ice, causing low sea levels and rising in warmer periods when the ice melted.

This meant Britain alternated between being connected to Europe via a land bridge to Belgium and Holland, and other periods when we were an island.

The River Bytham, although open to different interpretations, probably rose near Stratford on Avon, flowed north east past Leicester and then swung east through the Fens, out to sea south of Norwich.

At the time, the River Thames also flowed along a more northerly course, through Suffolk, when compared with today.

The huge River Bytham was effectively destroyed during the final and most extreme glaciation, the Anglican, when ice reached to where London is now.

It was after this that a huge meltwater lake formed in what is now the southern North Sea which eventually broke through at the Straits of Dover, about 8,000 years ago, creating our island and the rest, as they say, is history.

In doing this, the English Channel was eroded by a huge super river, which had the Rhine, Seine and the Thames feeding it as tributaries. It must have been a spectacular sight.