Travel to UK after CoS has expired

[tier2main]

Certificate of Sponsorship (CoS) as per https://www.gov.uk/uk-visa-sponsorship- ... rtificates is a document required to make your visa application. This certificate comes with a validity of 90 days. It's seen that some of the times the processing time for your visa to be stamped crosses 90 days. Also, many a times after the visa has been stamped, the travel gets postponed which means you end up travelling after your CoS has expired. Can we make a travel after the CoS has expired considering that one already has a valid work visa? What is the significance of CoS with regards to your travel.

[manci]

A visa must be applied for within 3 months of the date of assignment of the CoS.

Once you obtained the visa you can travel any time during the validity period of the visa.