Upvote:3
If the flights are on the same calendar day, and on the same ticket, then yes. Follow the purple signs for "Flight Connections" when you arrive. You will need to re-clear security at Terminal 5 Flight Connections, which regrettably often has a bit of a queue in the early part of the day.
If the flights are not on the same ticket but you have no checked baggage, then again you can follow the purple signs and advice above. You can obtain your next boarding pass at Terminal 5 flight connections, if you were unable to obtain it in Munich.
If you have a checked bag and you are travelling on multiple tickets, BA policy is present not to check through onto separate tickets, even onto their own metal. You should expect to go landside through customs and immigration.
Note that, since the UK is not a member of the Schengen zone, you will have to go through passport control to exit the Schengen zone at Munich and re-enter at Toulouse. France is in a heightened security state at the moment and you can expect some scrutiny at Toulouse.