She attended the Hurst Community School, Baughurst and later Queen Marys Sixth form college (QMC), Basingstoke.

[1] Her first major competition was the 1977 European Junior Championships in Donetsk, where she won three medals, bronze in the 100 & 200 metres and a silver in the sprint relay.

In Edmonton, representing England, she finished fifth in the 200 metres final in 22.95, narrowly missing a medal, before winning gold in the 4 × 100 m relay with Sharon Colyear, Beverley Goddard and Sonia Lannaman.

[3] Smallwood won her biggest individual title in 1981, winning the 200 metres at the World Student Games in Bucharest, in 22.78 secs.

Later that year, at the IAAF World Cup, she came in as a late replacement for Sweden's Linda Haglund, to run for Europe in the 100 metres.

[4] In August 1982, at the European Championships in Athens, Smallwood broke her own UK 200 m record with 22.13 secs, to finish a close second to Olympic Champion Bärbel Wöckel, who ran 22.04.

She won another silver in the sprint relay, along with Wendy Hoyte, Bev Callender (Goddard) and Shirley Thomas.

Then in October, at the Commonwealth Games in Brisbane, she won another silver medal in the 200 metres, in a wind assisted 22.21, being edged out of victory by Jamaica'a Merlene Ottey, who ran 22.19.

On day one of the championships, she won a silver medal in the sprint relay, alongside Joan Baptiste, Bev Callender and Shirley Thomas.

She then won the bronze medal in the 200 metres in 22.37, behind Marita Koch and Merlene Ottey and ahead of Florence Griffith.

In the 400 metres, she smashed the UK and Commonwealth record with 49.43 secs, behind the American pair of Valerie Brisco-Hooks and Chandra Cheeseborough.

With a strong late surge, she closed rapidly on Florence Griffith and Merlene Ottey-Page, who won silver and bronze in 22.04 and 22.09 respectively.

[6] In the sprint relay, drawn in lane one, she collected another bronze medal, along with Simmone Jacobs and two of her Moscow teammates, Bev Callender (Goddard) and Heather Oakes (Hunte).

Shortly after the Los Angeles Olympics, Cook won in London over 300 metres, edging out Chandra Cheeseborough.

The Great Britain and England Women's 4 × 100 m relay teams won a medal at eight consecutive Olympic (1980, 1984), World (1983), European (1978, 1982), and Commonwealth Championships (1978, 1982, 1986).