Water leaking between tiles in the shower

the tiles will need to come off and more than likely the wall behind might need to be replaced if its plaster board. The water would cause the adhesive to break down and rot the walls behind. the tiles could eventually fall off

It depends on how bad it's been leaking and for how long Normally you could not use the shower for a few days - stick a fan heater in the shower for the duraton and try to dry it out for as long as possible. If it's not too bad just re-grout. I'd only remove the tiles if they had become loose or there may be some trapped dampness ie soaking wet !

needs to be re siliconed

Hi Fiona, if the grout has cracked and there is water penetration you will need to remove the tiles and dry out the wall or replace depending on whether its a stud wall. Matt