Warren turned professional in the autumn of 1971 at the end of a hugely successful season during which he won the Duncan Putter, the Lytham Trophy and the English Amateur. He was also a part of that year's truimphant Great Britain and Ireland Walker Cup team at St Andrews and played an important part in that victory by teaming up with Michael Bonallack to defeat Lanny Wadkins and Jim Simons in the opening foursomes and then defeat that year's British Amateur champion, Steve Melnyk, 2 and 1 in the second series of singles. Warren had been seen as something of a star in the making when representing England at Boys and Youth level for five successive seasons between 1967 and 1971 but he never quite realised his full potential after turning professional, although he did win once on The European Tour at the 1985 Portuguese Open. In recent years, Warren has sent most of his time working as a TV broadcaster and will have considerable background knowledge of his competitors on the European Seniors Tour having spent the last two seasons working alongside Renton Laidlaw on the Tour's weekly news programmes.