It's interesting to compare this version with the later briefer one of 1997, since they are so different. The 1997 rendering is more concentrated and more efficient as a dramatization, focusing on the dramatic highlights of Marion confronting the expected patient at the asylum and finding someone else, and of the church fire scene, which is the dramatic finale of the book as well; but this so much longer version of 1982 is definitely better made. It sticks to the book, is more realistic, it preserves the wonderful Victorian literary style, making the language almost as enjoyable as Shakespeare, and above all, the actors are all so much more convincing, with Alan Badel unforgettable as the absolutely splendid villain Count Fosco is. Diana Quick makes an equally real and true Marian, and Daniel Gerroll is the perfect Walter Hartright.
There are many supreme moments in this dramatization, usually offered by the book, like Walter's surprising presence at the grave, how Anne Catherick is always accompanied by music which almost throughout for the rest is silent, except when Laura is softly playing, all the secondary characters like the church warden, Gilmore, the housemaid, while perhaps the most impressive presence of all, like in the book, is the stunning performance by Mrs Catherick in only the fifth and final episode (Pauline Jameson). John Shrapnel as the gross human failure of Sir Percival Glyde, a monster of a brute, is also perfect in his monstrosity, while Alan Badel as Count Fosco will remain the character you'll always remember with relish. Alan Badel was always phenomenally personal in his performances and always dominated the whole scene, and here more so than ever. This could be his very best performance.
On the whole, I must agree with most other reviewers, that this is the definite film version of perhaps the greatest thriller classic ever written.