asked the Minister of Pensions whether there has recently been any change in the conditions governing the granting of constant attendance allowances?

No, Sir.

Are these allowances granted for any specific time?

If a man's condition changes materially he may be given more.

Am I to understand that these allowances may be granted one week and taken away the next, or are they granted for a definite and specified time.

I cannot say that in every single case there would be a definite time. Obviously, if a man gets much worse he may get more.