...searching
Yes, an MOT certificate is still valid up until midnight on the date of expiry.
After this, the MOT certificate is no longer valid and your vehicle can only be driven if you are able to prove you are driving it to a pre-booked MOT Test appointment.
If you drive your vehicle without a valid MOT for any other reason, you can face a fine, points on your licence and, in extreme circumstances, a ban on driving.