How much will they cost, in money and other resources (for example, two design engineers for three weeks or one electrician for three days)? We can then see if the resources are likely to be available. In addition, though safety is important, we should not write blank cheques after an accident. If the changes proposed are expensive we should ask if the risk justifies the expenditure or if there is a cheaper way of preventing a recurrence. The law in the UK does not ask us to do everything possible to prevent an accident, only what is ‘reasonably practicable’