I have read on uk media that there isa long delay to replace passports .This will affect 90 day reports etc .What should i do ,as the wait reported as up to 4/5 months.Thanks 

It will have no effect whatsoever on your ability to do a 90 day report, etc.  You do not send your old passport with your application, just a copy of it, and you retain the old one for ID and immigration purposes until you get the new one.  The old one should not be used for travel though during the waiting period.  

As the British Embassy do not issue or advise on passport matters, this topic has been moved to the UK forum.