The army launched ‘Operation Searchlight’ to seize control of East Pakistan’s major cities and quell resistance; this became a full-blown genocide, with between a third of a million and three million killed and ten million more refugees fleeing to India. This had been foreshadowed by President Khan stating a month earlier that ‘kill three million of them and the rest will eat out of our hands’.
I can't really comment on the rest of the article - outside my area of knowledge. I can comment on the above.
Summary: That's putting it mildly. It was not merely a full-blown genocide, but it was also a deliberate and calculated attempt by the Pakistan Army to terrorise the local population into submission through the use of unspeakable atrocities. Inevitably, discipline among the Pakistan soldiers disintegrated, leaving just blood-lust.
Britain sat on the fence, her government talking about atrocities on both sides. She deployed the carrier HMS Eagle in the region ...
On a point of fine detail, HMS Phoebe was already in the region at the start of Operation Searchlight, and the Royal Marine contingent on the ship was deployed (with some difficulty) to the British Consulate in Dhaka to ensure that the genocide didn't spill over and affect the international consulates. A grand total of 12 Royal Marines (one of whom was 18, and on his first deployment) might not seem like a lot, but it had a number of consequences.
Firstly, whatever the British Government might have been saying about the situation, it was getting daily reports from people on the ground witnessing the one-sided nature of the atrocities. It might present a "both sides" face to the outside world. It also knew exactly that the objective of the Pakistan Army was genocide. And, of course, because the British Government knew, it is absolutely certain that the American Government knew as well. Intelligence was shared between the two, particularly regarding this sensitive part of the word.
Secondly, the Marines instituted a cordon sanitaire around the consulate (and later, consulates as other international consulates took advantage of our presence). There was stuff all we could do about what was happening in the city, but if it looked likely to impact the consulates, we were authorised to take the necessary steps.
This resulted in one of the gutsiest turns of phrase I've ever come across. The young Lieutenant in charge of the 12 Royal Marines (and with an army maybe 100,000 strong rampaging out of control) explained the situation to a very senior Pakistan General. "This is British territory. If your people threaten it's integrity, my orders are clear. So are my fields of fire."
By and large, the Pakistan Army accepted that limitation. Inevitably, a large number of civilians gathered around the walls of the consulate, creating a health situation. We dealt with that as best we could, although there was very little we could actually do.
The consequence of that was that, whatever the relationships between the Bangladesh Government and the British Government, there was a huge level of goodwill from the local people towards the Royal Navy and Marines.
I remain very fond of a comment made by an Indian Army officer after India intervened. He remarked that it was just like a Western film, only this time, the Indians came to the rescue of the beleaguered settlers.
Re: British reactions to the War of Bangladeshi Liberation. It's worth noting that Edward Heath was the only NATO Leader to be given the Bangladesh Liberation War Honour for foreign civilian leaders which was otherwise awarded to Indian, Bhutanese, Nepali and various communist leaders who had supported the Bangladeshi independence effort.
Two of my best friends had family in Bangladesh at the time, they both lost grandparents in the genocide, and as I spent yesterday with both of them, I showed them this article and we talked a bit about the effect of that national trauma and how it's still felt really strongly today.
Thanks for the comments @David Flin and @Youngmarshall . I found a lot of conflicting sources about the British government's position and didn't have your personal connections, so I decided to leave it as vague as possible.