How much time should I allow driving from Bristol to St Pancras Station ... need check in for Eurostar at 1700 on a Thursday?

The drive from Bristol to St Pancras Station is approximately 193 miles and can take between 2 hours 30 minutes and 3 hours 30 minutes, depending on traffic and road conditions. To ensure you have plenty of time to check in for your Eurostar at 17:00 on a Thursday, it would be advisable to leave Bristol no later than 13:30. This will allow you plenty of time to account for any unexpected delays during your journey and ensure you arrive at St Pancras Station with enough time to check in for your train.

It's always a good idea to check the latest traffic conditions and updates before you travel to ensure you have the most accurate information on the driving time.