Thomsen was a
Speedway World Team Cup winner with the
Denmark national speedway team in
1978,
1981 and
1983. Thomsen first rode in the United Kingdom with the
Wolverhampton Wolves during the
1974 British League season where he spent four years steadily improving his average. In 1978, he was signed by
Len Silver for the
Hackney Hawks in a swap deal with
Dave Morton, later becoming team captain in 1980. When Hackney closed at the end of the 1983 season, he moved to Poole Pirates for the 1984 season and rode for
Swindon Robins in 1986. ==World Final Appearances==