I rather support this statement.
There is a British culture based namely on Christian values. The idea of multi-culturalism undermines the values, undermines British culture.
Multi-culturalism, as it has come to be interpreted, has had the perverse consequence of threatening the very basis of liberal democracy that it was designed to protect.
...there is no straightforward contemporary answer to the question of what defines British national identity. Indeed, its own view on whether Britain should see itself as a secular state with which all religions must make their peace, or a Judaeo-Christian one that accepts dissident faiths...