APART from the Channel Isles, no part of the British Isles was invaded by Nazi Germany during the Second World War.

But during the darkest days of the conflict, the authorities has to prepare for just such an eventuality, and how this was done in Worcestershire is the subject of a book just published.

The Defence of Worcestershire and the southern approaches to Birmingham in World War II is by Mick Wilks, who five years ago co-wrote with Bernard Lowry The Mercian Maquis.

The earlier book told the previously unknown story of the Auxiliary Units, which has been set up in the greatest secrecy to fight as partisans against a German invasion.

The Defence of Worcestershire builds on the research done for The Mercian Maquis and looks more generally at the county's military preparations.

Both books draw on Mr Wilks's participation in the Defence of Britain project, a voluntary effort to record and preserve military heritage.

Before that, writes Mr Wilks in his introduction, "I, like probably many others, thought that Worcestershire was something of a military backwater, with little happening other than the various battalions of the Worcestershire Regiment training in the area or going off to garrison duty in the empire, or to fight aboard".

But that was not the case at all: the county was the chosen location for the government and the royal family, should they have had to leave London. It was also in a critical position on the way to Birmingham and the Black Country, home to so many vital industries, as well as having its own important factories. as well, of course, the scientific establishments in Malvern whose descendents are still with us.

It was thought that the Germans were planning an invasion through Wales, with blitzkrieg forces pushing through Herefordshire and Worcestershire towards Birmingham and the West Midlands.

The book shows how the defensive forces were organised to deal with the threat, with forces concentrated around centres such as Redditch, Malvern and Kidderminster to resist the onslaught. River crossings such as those at Powick, Upton and Bransford were also defensive strongpoints. The defences around individual locations such as airfields and factories are also discussed.

The Defence of Worcestershire is published by Logaston Press at £14.95. Logaston has also republished The Mercian Maquis at £7.95; it had previously been out of print and copies were selling for up to £25 on the internet. Both volumes are available from all good bookshops.