Hi Halifaxmum, I am a secondary maths teacher and on this topic I tend to agree with buenchico rather than with you, I'm afraid.
I find that in general a lack of knowledge of tables is a big hindrance to a student making progress in maths. It's very difficult to teach any topic in maths when pupils get stuck on simple multiplication and division. As Chris says, it detracts from the main topic being taught, whether it be algebra, area, fractions, etc. If a pupil struggles with simple calculations it tends to put them off maths generally.
I find division to be a real problem- so many pupils cannot divide 72 by 6, for example, whereas if you know your tables the answer should be clear straight away.
Yes, in real life we have calculators but in school and at work I feel you need to have a good appreciation of numbers and be able to do quick mental calculations without reaching for a calculator (or for most pupils now, a mobile phone). And of course there are some non-calculator papers at GCSE Maths.