Flower pots or concrete bollards?

I've just been for a week's holiday in Budapest enjoying the sunshine, the spas, the F1 grand prix, the restaurants...
I was struck by the similarity of the Hungarian Parliament building with the OK's parliament. Both are grand historic buildings. Both are on the edge of a river. Both have come to symbolise something of their nation.
But there's a subtle difference. Round the UK parliament there are defensive concrete bollards to prevent terrorist attacks. Round th Hungarian parliament there are wooden tubs with flowers growing in them.
It raises questions about what it is that we in the UK have done to make terrorism a threat.