Sir, I think calling it a mixed system or "Transplanted version of West Minister System" should be preferred.
I do not know whether they termed it as the West Minister system officially or not, this can easily be resolved by going through the documents recirding the debates of the Constituent Assembly, but I think even if someone said so, that sould not be treated as a gospel. Rather their mentality should be extracted and analyzed.
They had constitutional history in front of them, where we see the Government of India Act of 1935 did not prescribe a government form ehich can be term as completely based on West Minister System, and moreover, they were nationalist, orientalist and properly competent to work out something new and more compatible.
So they simply moved on for "legally transplating" the West Minister System into our polity. The another simple reason behind not calling it West Minister System by the constitutional academics should be- there are some distinctions at least, between our system and the traditional West Minister System which, although can be, but should not be ignored.
Isfar Tehami , thank you so much for this reply. Yes, I agree with your view that it is a "transplanted", adapted, modified or tailor-made system. Scholars have talked about these a lot. But considering the imitative nature of the over-all organisational framework of the system, it seems to suggest that framers were definitely adopting the structure of the Westminster Parliamentary Government.
It will be interesting to see whether they literally called it "Westminster" during the constituent assembly debates (I would appreciate if you could find and send me some relevant paragraphs from the debate, I currently don't have access to those).
Even if they did not literally call it "Westminster" did they explain why theirs is a adapted, transplanted or modified one? Did they say what marks the difference between their system and the Westminster system?
It looks like a never ending puzzle. They explicitly follow a system, don't (expressly) call it as such and later at opportune moments say on some occasion that ours is a Westminster system (when it appears convenient to do so) and, on other occasions, they would say ours is a transplanted one (without explaining what transplantation/modification they intended). Puzzling thoughts for the poor academics like us!!!
M Jashim Ali Chowdhury, That's an interesting problem, Sir. I also never found any such clarification in case of Bangladesh,(I have never gone any deeper with the debates of our Constituent Assembly). But I have gone through some parts of the collection of debates in Indian constituent assembly. I have never found them directly uttering the term "West Minister" although they never refrained temselves from bringing direct references from constitutional laws of Britain. It's true sir, constitutional history of both countries lack clarification on it.
For example, in case of India, previously I have heard an instance where the founding father of India brought the nature of British executive into their debate. I have just cross-checked it now. I found Prof. KT shah , member of Indian constituent assembly, while discussing the present article 74 of the Indian Constitution(art. 61 in the draft) in 30th December 1948, brought into question, the nature of Prime Minister's role either as a mere member of the cabinet or as a head of it. Here he also drew reference from British cabinet while the others tried to nullify it referring both British, Swiss and American constitutional laws. Although they were referring British constitutional law, and despite this issue is directly connected with the essential feature of "West Minister System", they never presented the British reference as an west ministerial one. I think they had a mindset of seeing the term West Minister as an integral part of British tradition and considered it as a colonial legacy and refrained from uttering this term. This might be true in case of our founding fathers as well.(this deduction is my personal observation).
However, sir, I will keep searching for the term West Minister in documents of both countries, and if found, Inshallah, I will be very honoured to notify you. This issue really attracts me. It was, indeed, an honour for me to talk with you, sir. Thanks.