which are the best safety locks for kitchen cupboards

We used the BabyDan Magnetic Drawer/Cupboard Lock. What I liked about them is that you don't have to add any screws to your cupboards as it uses a strong adhesive. The lock is opened and locked via a magnetic key. So advantage is you don't need screws but the disadvantage you need to have the key easy at hand.

My sister used the Clippasafe Cupboard Lock for her kitchen cupboards. They're excellent but the major downside is that they require you to put screws in your cupboards. I might give the BabyDan Magnetic ones that Walid recommend above a try.

If it is IKEA then they do their own range, I think I like the look of the BabyDan range

It depends on what kind of cupboards you have an whether or not you want to drill or stick things to the doors. I used a clip on my kitchen cleaning products cupboard as it works well with the handles. My daughter hasn't broken them or managed to open it yet. I use the wrap around stick on clips on my corner cupboards.