Raima,
Yes it is quite normal, I myself have been in and out of the UK many times and I have noticed that some of the stamps on arrival were missing. I don't think that should cause any problems. However, do keep note of these dates in case if you apply for ILR in the near future.

Thank You Mohammad,

As i am pakistani passport holder - is this going to be issue as i dont want hassle at aiport.

Raima

I am sure they wont bother you at the airport regarding a missing arrival stamp because of your nationality. When you report to the immigration at the airport, they would like to know about your most recent trip rather than your previous ones. So not to worry!

Hi Raima,

Heathorw Airport also has IRIS system, in which your eye(retina) shall be scanned & image shall be stored in their system. Whenever you arrive, you need not to go to immigration officer. Just go to IRIS system, this will let you go to in. So this is stamp free. There is no one to stamp your passport.

Deepak

I am a Pakistani passport holder and came to the UK in July 2008.

Whilst in the process of booking a holiday to Pakistan, I noticed, that
though I have a UK 'Limited Leave' visa, the passport has no actual
immigration stamp of me entering.

Can you advise if this is normal that passports are not stamped and that
this should not cause any issues on my return to the UK.

This is the first time i am leaving the UK since arriving in July 2008.