There is no excuse for being late to an interview, if you don't want the job then don't go at all, but if you turn up late you are as good as saying you don't want the job anyway and that if you do give me this job I will always late!

The Traffic was bad - You should have left earlier or planned your journey.

The Train was late - You should have got an earlier train.

My Nan died - Have some remorse and rebook.

I got lost - Get a phone with Maps, you're applying for an IT job.

I got the time wrong - Learn to read and learn to pay attention to detail.

OK so there may be some reason that really is beyond your control.  If you are going to be late, then let your recruitment consultant know so they can avoid the client wasting their time waiting for you and hopefully rebook the metting.

But ultimately, just don't be late.