Most Home Contents policies will already have as much cover as most people need for liability and bike damage. Policies will normally cover the policy holder(name on policy) and any family member in premanent residence in the household. Cover for non fault injury and loss of earnings are not so common, but may be available.
Be aware that limits will apply, such as exclusions for racing or testing etc., or fixed sums per bike, with security requirements when the bike is not in use. If the limits don't suit you should talk to your insurer.
As always, read the policy to be sure that you know what is covered. After all, that's why you are given the document. Don't be the type to moan about small print just because you are too lazy to read the document to see if you need to pay to have it amended to better suit your needs.
As already stated, cycling organisations such as the CTC or your local club will often include some cover in their fees and this could also be checked.
Don't be put off by the people who go on about the insurers fleecing you - they don't. As has been said, the personal insurance market is very competitive and most insurers make their profits elsewhere. Riding on the open road without, at least, liability insurance is a fools game.
As for the people who bemoan the compulsion of the likes of Motor Insurance; are they for real? Who do they think would pick up the bill for the carnage on our roads? People would be left to fend for themselves and the days of the workhouse would see an unwelcome return. Compulsory insurance only exists in areas where the vulnerable are at the mercy of others on a large scale - Motor Insurance and Employers Liability insurance - and the need for financial provision is great. To bemoan that is to admit a personal uncaring attitude towards the misfiortune of others on the basis that it can't happen to you; it can, and it may!