I am trying to figure out what kind of smoke alarm I should buy. I live in a flat but was thinking it would be good to get one that is somehow linked to all the flats that are in the house. Are they more effective than individual alarms?

I would suggest you speak to your landlord or managing agent if you own the flat, because the common areas are subject to the Regulatory Reform (Fire safety) Order 2005 and you need to know the fire strategy for the premises and details of the fire risk assessment. Also consider if you interlink each flat what happens if one of your neighbours keeps on burning the toast?

You mention that your flat is in a house so it is most likely been converted to self contained flat. The FSO will apply to the common area of the house as such it is common to find an AFD system installed in the common area. There should be a minimum of 75db at the bedhead, for this reason sounders in each individual flat would be required. This would be the only interlinking of the flat with regards to an AFD.

There is a lot more to consider though and the FRA should identify what is required as stated by Tom