H.B. 

R.A. have invited Govt. to buy at a large figure.  With Ty. consent
  P.M. declined.  They were not surprised.  They decided to go
  on with sale, by auction.  Press have now wormed this out of
  them.
 Possible courses.  i) nothing  ii) offer subsidy to R.A. - but they say
  they don't want it.  iii) offer Govt. contn to a national fund to
  buy the picture at auction.
 Let public opinion develop before deciding on iii) - the most likely
  course.
 P.Q.'s for 22/3.  This gives us time.
 Sir C. Wheeler thinks it will be bought in this country.
 Agree we shdn't encourage public appeal.  But can't we give time
  for this to happen spontaneously.

Taken from C.C. 16(62) - Meeting held on 26 February 1962