According to The Lawn Expert,the best time to aerate is September - but only the areas which show obvious signs of compaction, it is not necessary to do the whole lawn. Symptoms of compaction will be areas that go brown quickly in summer, areas where water collects and doesn't drain rapidly when it rains, areas that are regularly walked over, or where children play frequently.

It's mild now - but it probably won't remain so. If you're desperate to do it now, I suppose you could risk doing some of the worst patches, but I wouldn't recommend it once this mild snap is over and we're back to low temperatures.

From what I have learned, better not to do when the soil is soggy, and nearly impossible when the soil is frozen. If you can do it, be sure to tug back on the fork to crack the soil every time you drive it in, or you will just be compacting it more.

Have you seen those spiked roller gadgets that you just push along? Don't know how effective they are

Ok. Will leave it a while. Steragram-I got one of those spiked roller gadgets and they’re useless!! They don’t penetrate the soil to any significant depth. I might hire a petrol one in the spring although I’ve been told some elbow grease and a garden fork is just as effective....

I would agree that it's best to keep off the lawn until it starts to dry out in spring. I did however borrow one of the sprung push-along lawn spiker and I have to admit that it was quite exhausting trying to push it. Like Amsterdam suggests, I would consider hiring a petrol machine eventually.