Sorry...
I'm planning to leave Maida Vale at 8am. Eurostar train at leaves at 9:24. Google says 25 mins to St. Pancras, leaving me 30 extra minutes for the security and/or delays, based on Eurostar telling me to be there 30 mins before departure.
So... is change at Baker to Metropolitan the most efficient way to get there in that timeframe? We can leave earlier of course. The marketing for Eurostar *claims* security to not be like an airport, but I'm not sure if that's accurate.
The 10 minute boarding is based on the Eurostar site saying business class travelers can get there 10 minutes before. Surely there's security for them as well.
"Standard, Standard Premier, and Eurostar™ carte classique travellers
Check in at least 30 minutes before departure, 45 minutes at busy times like weekends and bank holidays.
Business Premier and Eurostar™ carte blanche travellers
Check in at least 10 minutes before departure."