asked the Chancellor of the Exchequer what is his estimate of the loss of revenue in terms of income tax and national insurance contributions in the last 12 months, arising from strikes, divided, if possible between (a) strikers' income and (b) total loss of revenue, including that from workers laid off as a result of strikes.

I regret that no estimate can be made since there is insufficient information about the income of strikers as such, or about the income of those laid off as a result of strikes.