Radcliffe's time of 2 hours 15 minutes and 25 seconds was set when the now-retired British distance great won the 2003 London Marathon.
However, her time was initially regarded as a 'world best' rather than a 'world record' by some in athletics because it was set in a race where men were running rather than in a women's-only event.
Keitany is aiming to become the overall fastest female runner in marathon history on April 22, having set the women's-only record when she won last year's London title in a time of 2:17:01.
That saw the 36-year-old Keitany beat Radcliffe's women-only world best of 2:17:42.
At the halfway stage of last year's race, Keitany was a minute quicker than Radcliffe had been at the equivalent point in 2003 only for her pacemaker to drop out soon afterwards. Out in front on her own, Keitany's pace flagged.
"The marathon world record is something that I have been working towards for several years and I feel I am now in the position where I can really attack the time of 2:15:25," Keitany said on Thursday.
She said that last year "I was feeling good but it was hard to run nearly half the race on my own. By having male pacemakers, I will be able to have the support throughout the race.
"Obviously, any world record is contingent on everything being right on the day," she added. "London has shown it has the course for world records to be broken and I hope my form and health stay strong and that the weather is kind on the day."
Hugh Brasher, the London Marathon's event director, emphasised the scale of the challenge facing Keitany by saying: "No one has got near Paula’s mark for 15 years and for Mary to commit to attacking it shows her courage and the belief in her athletic ability."
Keitany could have more than just the clock to contend with in London. The women's field is set to feature Ethiopian rival Tirunesh Dibaba, a triple Olympic gold medallist on the track, and Kenyan-born Bahraini Rose Chelimo, the 2017 marathon world champion.
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