Double amputee Oscar Pistorius dream of competing in the 400 metres event at the London Olympics has come to an end.

Double amputee Oscar Pistorius secured a silver medal at the African Athletics Championships in Cotonou, Benin, on Friday, but his dream of competing in the 400 metres event at the London Olympics has come to an end.

Pistorius clocked 45.52 seconds to finish second in the final of the one-lap sprint behind Isaac Makwala of Botswana, who won gold in 45.25.

Another South African, Willem de Beer, clinched bronze in 45.67.

Pistorius needed to record the Olympic qualifying time of 45.30 to secure his place in the individual 400 metres event at the able-bodied London Games.

The 25-year-old 'Blade Runner' set a season's best of 45.20 in Pretoria in March, but he needed to reach the mark again by Saturday's deadline to meet South Africa's stringent qualifying criteria.

Pistorius could still compete in London as part of the SA 4x400m relay team, with the country's final Olympic squad set to be named next week.

Middle distance runner Andre olivier, meanwhile, booked his place in South Africa's Olympic team with one day left before the qualifying deadline.

Olivier, 22, bagged the bronze medal in the men's 800m final in 1:45.09, dipping under the 1:45.60 qualifying standard.

Taoufik Makhloufi of Algeria won the continental title in 1:43.88.

Two other South Africans, Tsholofelo Thipe and Ruben Ramolefi, failed in their final bids to book their tickets for London.

Thipe was fifth in the women's 400m final in 52.26, missing the 51.55 mark she needed to set, in a race won by world champion Amantle Montsho of Botswana in a championship record of 49.54.

Ramolefi, who need to clock eight minutes, 23.10 seconds (8:23.10), finished seventh in the men's 3 000m steeplechase final in 8:29.53.

National record holder in the 400m hurdles, LJ van Zyl, who has struggled with injury in the build-up to the London Games, did not start the final of his event, after qualifying in a pedestrian 51.87 seconds in the semi-finals on Thursday.

Van Zyl has already qualified for the Olympics. – Sapa