Is it illegal if a person dies during surgery and there is no time of death present on the certificate?

my nan died during minor surgery and there was not a time of death recorded! its very undignified and i would like to no why we haven't been told! we suspect that it was due to suspicious circumstances of how she died as she had an abnormality that if ignored or the operator was unaware of it, the surgery would of had to been done more causious due to her admonality! if they did not inform the surgeon then he would have carried out the operation as normal and that would most definatly of caused her a very seriouse bleed from the aorta and death! do you think that they would hide the time of death due to maltreatment? hope i get to the bottom of this and get some justice for my wonderful nan.

no, often it is impossible to give a time of death, if for example someone was found dead in their house and had been there for a day or so - you can only record the date of death and don't need the time at all.
However, you clearly have concerns about the treatment that your grandmother received. I would WRITE to the hospital trustees or directors - not to the consultant - and ask for a record of events and a listing and schedule of the care and drugs that your nan received, etc. They may protest, but you are entitled to this. Push hard to get something put in writing about the treatment she had and the surgeon's findings. Then, if you still feel that you aren't satisfied, you may wish to consult an independent surgeon and ask his opinion and perhaps take it further with a specialist solicitor.
But, before you go in with all guns blazing, do think hard about what you are trying to do - none of this will bring your gran back. The hospital may have diagnosed her based on what they could find at the time - with hindsight we'd all be a lot wiser and do something different. Only push for justice if you really feel that somebody has been negligent in their care of your gran.

I would go to citizens advise they will point you in the right direction.Sorry on your sad loss

No its not illegal. There is no legal requirement for a time of death on a death certificate.