A few people have also suggested that is unlawful to insert a clause preventing a member of staff from recruiting former players but there are a few precedents including this one involving Frank Arnesen:
http://www.timesonline.co.uk/tol/sport/football/premier_league/tottenham/article624838.ece
http://www.timesonline.co.uk/tol/sport/football/premier_league/tottenham/article624838.ece

