Stability of supporting structure
3. Any supporting structure shall –
(a)be suitable and of sufficient strength and rigidity for the purpose for which it is being used;
(b)in the case of a wheeled structure, be prevented by appropriate devices from moving inadvertently during work at height;
(c)in other cases, be prevented from slipping by secure attachment to the bearing surface or to another structure, provision of an effective anti-slip device or by other means of equivalent effectiveness;
(d)be stable while being erected, used and dismantled; and
(e)when altered or modified, be so altered or modified as to ensure that it remains stable.