He made his athletics debut at seventeen at a national school championships after being persuaded to attend by a friend, and won a gold medal. He went on to represent the United Kingdom at the Paralympics in
1984, winning silver in the
B3 400m. At the
1988 Seoul Paralympics, Thatcher won gold in the
B2 800m and silver in the B2 1500m, behind
Mariano Ruiz of
Spain. Four years later at
Barcelona 1992, he took the gold medal in the
B2 1500m; the silver in the B1-B3 4 × 400m relay alongside Simon Butler, Andrew Curtis and Mark Whiteley; and the bronze in the B2 800m. Thatcher was a double gold medal winner at
Atlanta 1996, triumphing in the
T11 5000m and 10,000m. At the
2000 Sydney Games, in the T12 class, Thatcher took gold in the
5000m and bronze in the 10,000m. Thatcher carried the flag for
Great Britain at the
opening ceremony of Athens 2004, and competed in the
T12 5000m and
T13 10,000m, narrowly missing out on a medal by finishing fourth in both finals. ==Personal life==