Come on guys lets be realistic, 100% security is impossible.
An idiot journalist is likely to be able to do this almost anywhere, and achieves nothing other than hand wringing on here about who should or should not be 'blamed' for the security breakdown!
Compare this to the recent crash of a B777 at Heathrow, likely to be caused by something no-one had foreseen; this happens in security too.
I once heard security described as 3 brick walls all built parallel to one another and all having some holes in them; when the holes line up you have potential for a disaster.
The best thing we could be doing is condemning the idiot newspaper who set out to prove this complacency, as it encourages others to have a go, including real terrorists. If you want to help the enemy then keep publicising idiotic stunts like this one.