Both of the defending champions are returning to compete in Sunday's Watford Half Marathon.

Paul Martelletti was the men's winner 12 months ago after recording a time of 1.06.52 and will be back to defend his title this weekend.

But his closest challenger and previous winner Yared Hagos will not be competing this year in the Watford race.

In the women's competition, Victoria Knight is also hoping to repeat her victory from last year. Knight won her event with a time of 1.18.16 12 months ago.

But she could face competition from Hayley Munn. The highly-rated runner won the Wokingham Half Marathon last year and is expected to challenge for first place on Sunday.

Race organiser Richard Parles said: "Hayley will be the favourite on paper because she has run faster.

"But Victoria has the advantage of knowing the course well from last year so this could help her chances.

"Hayley is two minutes faster so has to go into the race as a pretty strong favourite."

There will also be several professional triathletes taking part in the race.

Lucy Charles and Natalie Lawrence will be in the women's event while Reece Barclay will hope to make an impression in the men's run.

The record for the men's race was set in 2007 by Tomas Abyu in a time of 64.50 while the women's event was achieved during the same year by Liz Yelling in 73.42.

Parles said: "I don't envisage a course record in the men's because there aren't that many expected to challenge Paul Martelletti. But in the women's race there are quite a few quality entrants so it should be a good race."

He added: "It is in reasonably good condition, we've had good entry and plenty of helpers again this year so we're expecting it to be a successful event."

The forecast is set fair for this Sunday with cool but dry conditions expected.

Parles said: "It is currently looking good for the race day. It should be 7 or 8 degrees and dry in the morning although it may be a little bit windy."

The course layout is being kept exactly the same as last year which means competitors will again face the demanding Deadman's Ash hill in Sarratt.

Entry closed at the start of this week with 2,400 entrants confirming their participation. The amount of runners to finish is predicted to be around 1,900.

Sunday's race also acts as the county veteran championship. This is for women aged 35 and older or men aged 40 and above with around 250 expected to compete.

This year the juniors race has been postponed and will now be held as a standalone event on Sunday, March 20.

There is likely to be traffic congestion near the course with a number of roads closed during the morning.

Parles said: "There will be serious congestion and it's best to avoid certain areas. Langleybury Lane and Grove Mill Lane will be shut as well as the route from Chipperfield to the Clarendon Arms.

"A few roads on the Cassiobury estate will also be shut from about 10.30am until around 1pm."

The Watford Half Marathon gets underway at 10.30am on Sunday with the start and finish taking place as usual in Cassiobury Park.