The Vickers Valiant was an all electric aircraft. Undercarriage, flaps, airbrakes(?) and bomb doors. Even the flying controls were operated by electro-hydraulic units descended from the Frazer Nash gun turret. No problem with locking the bomb doors as one crew found out after a few days on the wazz in the USA on a Lone Ranger.
The battery had gone flat.
You couldn't charge the battery until the battery contactor was made which required battery power and they were in the bomb bay and you couldn't open the bomb bay until you had electrical power.
Eventually after a lot of crawling around underneath the AEO's position the AEO manage to connect a set of borrowed jump leads from a fire truck to the contactor's terminals. This enable the external power to connect to the aircraft and then they could open the doors.
The reason the battery had gone flat was the old chestnut common to cars. They had left the bomb bay lights on when they closed them up for the night.