This made-for-TV movie is hard to find now. It was shown in the US on PBS in the early '80s. I've not seen it since nor found many references for it.
It has a fine cast drawn mostly from British television. John Thaw (Francis Drake) is probably best known for playing the lead in the INSPECTOR MORSE series. Paul Darrow (Thomas Doughty) will be remembered as Avon in BLAKE'S 7. They are especially effective but all the cast does well.
The script is engaging and fairly accurate. A real replica of Drake's ship, THE GOLDEN HINDE, is used which adds to the verisimilitude, as do the costumes and sets. All in all, this is an excellent historical drama and I wish it were available on DVD.