Oxfordshire suffered major flooding for the third time in a year today as the county's infrastructure failed to cope with a heavy deluge.

Roads were closed, schools shut, rivers put on flood warnings and watches, and some houses flooded as almost two inches of rain - more than 75 per cent of an average June rainfall - fell.

An overrun of surface water has been blamed, and Oxfordshire officials said that although work had been done to improve flood defences ultimately we were at the mercy of extreme weather.

Geoff Bell, the Environment Agency's area flood risk manager, said the organisation was doing all it could to reduce the effects of flooding and had recently spent £1.8m to tackle the problem.

Mr Bell, whose organisation is responsible for the county's rivers, said: "You can't predict exactly when and where rain will fall and unfortunately flood plains flood, that's the natural system.

"We have had all our people out making sure that drains are clear and blockages have been removed, but however much maintenance we do unless the capacity of the drainage system is massively increased it is always going to be overwhelmed by floods like this."

Oxfordshire County Council said it had worked on 20 key highway drainage schemes and had another 15 planned.

Head of transport Steve Howell said: "It will never be possible to eliminate problems altogether, however we are in a better position across the county now than in previous times."

Fire crews dealt with more than 120 emergency calls as at least 12 roads were closed.

At Peers School in Oxford, hundreds of pupils were sent home after teachers decided it was unsafe while others had to sit GCSE exams.

Headteacher Ed McConnell said: "We had hundreds of soaking wet children with still four hours of school to go."

Pupils at Witney Community Primary School were also sent home.

Flood levels reached 2ft in Wheatley after water streamed down High Street, flooding a number of homes in Crown Square.

Father-of-two Christian Guthier's home was six inches under water and he said: "It was coming in everywhere through the doors, windows and pipes - it was like having an inside fountain."

Firefighters were called out to assist pensioner Iris Lancaster after she was flooded for the third time since last July.

Water swamped her back garden and leaked into her conservatory. Her daughter, who lives next door, was also forced to sandbag her back door after water seeped into her kitchen.

The family, who live at 68 and 70 Kennington Road, Kennington, blamed the latest incident on a broken culvert.

Mrs Lancaster, 82, said: "This is the third time we have been flooded since July.

"It's frustrating because you are helpless. We grabbed everything we could to throw on the floor, but you can't fight water - it just comes all of a sudden.

"It washed down like a hurricane this morning.

"We want the culvert repaired so the water runs into the stream, but nothing ever seems to be done."

An engineer from Thames Water visited the property yesterday afternoon to assess the situation.

In Witney, a man took the law into his own hands to save his elderly parents' home from flood water being washed into it by passing cars.

Stephen Aldridge decided to close the town's Hailey Road himself with cones and a rope when two feet of water gathered just yards away from their house.

He said: "I could not believe it, no one closed the road, so I decided to do it myself. My parents are both elderly and their home was flooded last July from the wash of cars. I'm not having a repeat of that."

Mr Aldridge rushed to his parents' as soon as he saw water gushing from nearby fields past his own home in Eastfield Road.

Mr Aldridge's parents, James and Tricia, live in the last house in West End, a natural dip that collects water streaming down Hailey Road because the drainage system cannot cope with heavy rain.

The water was up to the top of the front door step at 3pm yesterday.

A spokesman for Oxfordshire County Council, responsible for road closures, said they had been "inundated with calls" and were not aware of the position in Hailey Road.

In Wendlebury, some homeowners had just returned to their homes from last summer's floods to be greeted by two foot of rain water and sandbags lined the street.

A row of homes in Thame Road, Tiddington, and houses in Kidlington and Kennington also had rain water pumped out by fire crews.

Flooding also reached 2ft deep in Barton Village Road, Barton, in Oxford.

Fire crews also dealt with flooding in Thame, Chinnor, Wheatley and Witney.

Roads closed included Mill Lane in Chalgrove, the B4044 from Botley to Farmoor, The Garth in Yarnton, A418 in Tiddington, A40 in Wheatley and Goosey Lane in Goosey.

Closures were also in place on the A417 west of East Challow and the A338 at East Hanney.