THOUSANDS of athletes face transport disruption as they limber up for today's Great South Run.

Up to 25,000 people are set to take part in four events across the weekend, including Sunday’s 10 mile run.

But train companies are warning passengers of changes to planned routes as improvement works at Fareham station start this weekend.

Due to train works in the Fareham area which started today there are no train services from Southampton to Portsmouth.

A bus replacement service will be in operation but will run to Havant due to road closures in the Portsmouth area.

From Havant, trains will operate a frequent service to Portsmouth Harbour where runners can expect a 25 minute walk to the start line.

The Great South Run starts and finishes in Southsea and features a 10-mile course that has been graced by world-class athletes such as Liz McColgan, Paula Radcliffe, and Sonia O’Sullivan.

You can relive the magic of last year's event with our photo gallery from Great South Run 2015 above.

Among the runners making her debut this yeat at the Great South Run is Daily Echo reporter Sian Davies.

The mum-of-two was as shocked as anyone to be preparing for the race after her husband Scott surprised her with an entry place last Christmas.

Daily Echo:

Sian, 38, above, said: “I was unwrapping the present thinking it was the weekend break I had been dropping hints about. Instead it turned out to be an information pack for the Great South Run!”

After getting over the shock, the novice runner began her training regime which included taking part in the ABP 10KM run earlier this year.

Now she has stepped it up to take on the GSR and has even more motivation as she is also raising cash for Naomi House and Jacksplace children’s hospices.

“It does spur you on to think not only am I taking on a personal challenge but also raise much needed cash for a wonderful organisation that does so much to support families of children with life limiting illnesses,” Sian added.

If you would like to donate to Sian’s running fund visit bit.ly/2cOOHZd.