The 43-year-old Briton's comments come just days after the International Association of Athletics Federations (IAAF) confirmed that Kenya's Olympic marathon gold medallist Jemima Sumgong had failed an out-of-competition drugs test.

Sumgong tested positive for the banned substance erythropoietin (EPO), a hormone which boosts red blood cells.

The IAAF revealed that a case has been opened this week against the runner, who triumphed in the women's marathon at Rio 2016 in a time of 2 hours 24min 04sec.

She became the first Kenyan woman to claim the title, finishing in front of Bahrain's Eunice Kirwa and Ethiopia's Mare Dibaba.

Sumgong was poised to be on the start-line for the London Marathon, an event which Radcliffe has won three times, on April 23.

"The costs for those who cheat have to be made much greater," Radcliffe told BBC Radio 5 live's Sportsweek.

"I do advocate making doping a criminal offence so that you can face criminal sentencing and criminal sanctions.

"If it became a criminal offence it makes it easier to track and be able to search where you have strong suspicions."

Radcliffe has been an outspoken campaigner against drugs in sport during and after her career.

She faced allegations in some sections of the media in 2015 that she had blood-doped before being cleared by UK Anti-Doping and the IAAF.

Sumgong faces the prospect of being handed a ban by the IAAF should her B-sample come back positive.

London Marathon chief executive Nick Bitel confirmed the positive followed an Abbott World Marathon Majors (Abbott WMM) funded drugs test and vowed to take strong action.

Tim Hadzima, Abbott WMM general manager, has revealed that they will not name a women's champion at the end of the series while the case is ongoing against Sumgong.

Kenya is an athletics powerhouse, particularly in long and middle-distance running, and topped the medals table at the 2015 IAAF World Championships in Beijing.

The country, however, has regularly been tainted with drugs problems.

Around 40 athletes from the nation have tested positive for banned drugs since 2012, including three-times Boston Marathon winner Rita Jeptoo, who failed for EPO in 2014.

A new law criminalising doping has been introduced in the country, which was declared non-compliant by the World Anti-Doping Agency (WADA) in May to put participation at Rio 2016 in jeopardy.

WADA said Kenya were in breach of anti-doping rules before the situation was resolved in time for the Olympics.