Is it allowed? Current home insurance (not M+S) including contents covers bikes up to £250.

M+S contents is £150- can I buy this as a top up?

There's an insurance concept called "Contribution" which means that if you have two policies covering the same thing, they'll each pay their own proportion of the loss. So if one policy has a bike limit of £250 and the other has a limit of £400, you don't get £650 if your bike gets nicked (assuming it's worth that much), the two insurers share the first £250 and the other one pays the next £150.

I was assuming I would only claim on one policy- this not correct?

I'm confused then, sorry. You want to top up the limit on one policy by taking out another, but you'd only claim on one of them? Which one?

I was assuming I would only claim on one policy

Pretty sure that would be fraud, and if they found out not only will you be in trouble but you'll never be able to buy insurance at a reasonable price again. So don't do it.

Curent insurance covers house and contents.

I want to take out M+S contents insurance at £150, to cover my bikes only. Nothing else.

If the bikes went, I'd phone M+S only.

Confused re. fraud comments!

Yes you can do this.

No it's not fraud.

It's called dual coverage. This can work two ways either in the manner Nedrapier initially suggested or alternatively one insurer coughs out up front then seeks to subrogate costs afterwards to other holding insurers.

Ah, with you now.

There might be something in your current policy which excludes damage to property more specifically insured on another policy, this would probably mean that "M&S contents only" would be more specific than your current house and contents, so only M&S would be liable to pay anyway.

Probably best to call your current insurers and ask them to take off the contents? You might get a small return premium (which might be outweighed by the admin charge!)

On the other points, it would only be fraud if r3g was claiming full amount from both policies, in order to be better off than he was in the first place. And subrogation is when the insurer, reclaims from the responsible party (in this case, would be the thief), not from another insurer.