Benita Johnson will use Sunday's Vattenfall Berlin half marathon to send out a warning to her London Marathon rivals.

The former world cross-country champion believes the Berlin event will offer the ideal opportunity to put the final touches to her preparations for London.

Johnson believes the presence of last year's winner, Edith Masai of Kenya, will provide the test she needs.

Masai, the four-time world cross-country short-course champion, scored a stellar win 12 months ago ahead of Olympic marathon bronze medallist Deena Kastor.

Johnson 28, said: "Everything I've done in the last few months has been focused towards London and I'm in the best shape of my life.

"Berlin offers the ideal chance to have one tough final race and given how good my training has been, I'm expecting to run really well.

"I'm not thinking of what time I will be running, it's a fast course and obviously my major target is winning. But Masai will make it very tough."

She added: "London is what it is all about."