We will put our hands up - our selection is open to a little debate. Our logic is as follows. First, we wanted to walk all the 'historic counties'. Second, we wanted to ensure that there was a reasonable distribution of walks around the country. Third, we sought to exclude walks of low interest. And of course 50 is a nice round number - challenging but eminently doable.

So our list starts with the 39 historic counties - including Westmorland and Huntingdonshire and recognising the division between East and West Sussex (they have had separate county councils since 1888). A debatable exclusion is the Isle of Ely - see Wikipedia to examine its claims to county status.

A number of issues surround the biggest historical county, Yorkshire. It was divided into three Ridings. North Yorkshire exists now as a county and its high point is Whernside (under the old boundaries, Mickle Fell - now in Durham - was the North Riding peak). The East Riding summit of Bishop Wilton Wold (or Garrowby Hill) is included, albeit under the label of the short-lived county of Humberside. We may shift back and give it the East Riding label. West Yorkshire does not exist now as an administrative unit - it is divided into five unitary authorities. Nonetheless, we believe it's worthy of inclusion - and it is the tenth highest of our peaks. (Incidentally, Whernside is the old West Riding high point - complicated isn't it?). We also decided to include South Yorkshire - created by that notorious bureaucratic meddler Ted Heath in 1972. This was a simple decision: it exists as a county and the walk to High Stones is a cracker.

That gave us 43 potential destinations, albeit there was a further issue of 'principle' to resolve. Some county boundaries have changed over the years, with the result that a few peaks have moved from one place to another. Bald Hill was once the pride of Oxfordshire only to be replaced by Whitehorse Hill in 1972 (much to the chagrin of Berkshire who lost the famous White Horse of Uffington). Oliver Hill gave way to Cheeks Hill in Staffordshire. For the sake of simplicity, we decided to choose the county top standing within the current boundaries of the historic counties.

We had seven extra counties to find. Of the potential candidates two were certainties. First, London deserved inclusion based on sheer historical importance. (And the London summit had to be the one truly in London. So our walk is to Jack Straw's Castle ahead of various outcrops on the North Downs that were once included in the GLC.) The Isle of Wight too, as a nice compact geographical unit and a great place to visit, had an unanswerable case for inclusion.

Choosing the final five was more difficult. We restricted ourselves to places that had once achieved county status - a unitary authority does not cut the historical mustard. Then we introduced a subjective consideration - were they worthy of a weekend visit? On this basis our choice has fallen upon Avon, Cleveland, Greater Manchester, Tyne & Wear and the West Midlands. However, all you fans of walking in the ex-county of Merseyside, we are open to persuasion.

In most cases, yes. In a few counties there is some element dispute. This is the case in Lancashire, Dorset and South Yorkshire. In all cases our routes take in both peaks - just to make sure.

In Lancashire the debate is between Green Hill and Gragareth. (Sorry, this has still to be written up.) In Dorset, the argument is between Lewesdon Hill and Pilsdon Pen - the former having grown in people's estimation in recent years. (Click here to view a newspaper article on the 'controversy'.) Meanwhile, our South Yorkshire walk will take you to High Stones and Margery Hill.

The other dilemma is posed by Nottinghamshire. We favour the man-made peak of Silverhill over Newtonwood Lane. There seems to be little doubt that this is the highest point and it makes for a better walk. (By the same token, if the amazing man-made Silbury Hill in Wiltshire was that bit taller we would have had no hesitation in including that in our list.)