AS a nation we are often criticised for being predictable, but if there is one thing which is unpredictable about this country it has got to be our great British weather. It can prove useful, though, when we want something to blame for our ills.

The weather has been blamed by Railtrack managers to explain a recent five per cent increase in passenger delays on our train lines during the last three months, and GNER has blamed rain and floods for a poor punctuality record in June.

Railtrack said the wettest April since records began and the wettest May for 17 years had caused signals to short-circuit and automatically ''fail'' on red.

More delays came on June 19 when temperatures soared above 30C (86F) causing tracks to buckle. The weather has been giving rail chiefs more headaches this week as weeds, particularly buddleia, break out across the country's tracks.

Railtrack chief executive Gerald Corbett says: ''The challenge is to deliver a railway that does not freak out with the weather.''

At the moment it's wet, wet, wet, so at least we won't have to worry about the spectre of water shortages or having to queue at a stand-pipe at the end of the street. Will we?

Well, apparently heavy rain doesn't even necessarily mean a plentiful supply of drinking water and Environment Minister Michael Meacher says the torrential downpours should not mean that we should ignore water conservation.

He says drought conditions similar to those experienced in the 1990s could hit the country within a year, because of climate change.

''Climate change has become more apparent, ranging from the drought we had in the early and mid-1990s to the current rainy period. But let us be clear that droughts are going to occur, and it could be next year, so we should take precautions,'' he says.

Which basically means that while we are running for cover from the storm clouds we should be double-checking to make sure we have left the rain tub uncovered.

And there is little comfort from the fact that so far this month we have had less than half the normal amount of sun we would expect in July.

According to experts, the current weather is down to what has been dubbed the ''rope-wave'' effect. When you flick a rope in your hand, it bends into a wave of evenly spaced peaks and troughs which do not move even though the ropes does.

This is what has been happening to the jet stream, the undulating current of wind that blows from west to east across the northern hemisphere, just a few miles above our heads. As the jet stream bends from north to south it creates eddies of air - high pressure at its peaks, depressions in the troughs. Every so often it gets stuck and it is our bad luck to be trapped under an unshifting depression.

The wash-out summer also takes its toll on many organised outdoor events and sporting occasions.

Travis opened this year's Party In The Park in London's Hyde Park with their hit Why Does It Always Rain On Me? After 20 minutes, the heavens opened.

And this year's Wimbledon men's tennis final was punctuated with wet spells, meaning the women's doubles final was postponed until the following day.

The general gloomy weather means that those suffering from Seasonal Affective Disorder (SAD) get little respite from their winter woes, while summer colds have a field day spreading among commuters like wild fire.

The recent heavy rain combined with hot temperatures also means problems for gardeners. As well as having to cut the lawn almost continually, weeds are now rocketing out of control.

A Royal Horticultural Society spokesman says: ''Wet weather causes weeds to thrive and leads to an increase in diseases in the garden. The first thing that people will notice is potato blight which also affects crops like tomatoes. Downy mildew will also start to affect other plants.

''Fruit such as raspberries like wet weather, but only when it is cool. We have been experiencing hot, wet weather which causes fruit rot. The weather will also have an effect on later fruit crops.

"On the other hand, if it wasn't for our changeable weather we would not be able to live in such a green and pleasant land."