And yes, he is one of those Whitbreads. There was quite a tradition of London brewers entering parliament.
"Mr. WHITBREAD stated, that many of the respectable persons concerned in the brewing trade felt themselves much aggrieved by the expression of an Honourable Gentleman (Mr. Vansittart) on a former evening, that his reason for proposing an additional duty on the importation of opium, was to prevent the brewers from using it in the manufacture of beer. Now he wished the Honourable Gentleman to state whether he meant to apply that allusion generally, for he could assure the House that long as he was acquainted with the brewing trade he never knew of any such ingredient being employed. On the contrary, he was aware that a very severe penalty would attach to the use of it. If, therefore, the Honourable Gentleman was in possession of any information that such means were resorted to to adulterate the beverage of the public, it was his duty to prosecute the guilty parties, and not to throw out any general imputations.Evidence but not good enough to get a conviction? Sounds more like rumour or supposition.
Mr. VANSITTART, in reply to the Honourable Gentleman, said that Government had received information sufficient to justify the statement alluded to, but not such as to furnish legal proof of guilt in a Court of justice, but he assured the Honourable Gentleman that he did not at all intend to insinuate any thing as to the use of opium against the London brewers.
Mr. WHITBREAD observed, that it was incumbent on the Honourable Gentleman to propose every precaution for the security of the health of the People, and thanked him on his own part and that of all the Gentlemen concerned for the explanation he had given.
Mr. VANSITTART again disclaimed any intention of throwing out a general insinuation, but that from the information he had received, coupled with an account that a large quantity of opium was about to be imported, he felt it advisable to recommend the advance on duty alluded to.
Mr. LANGMEAD said, he had been above thirty years engaged in the brewing trade, and that he never heard of such a thing as opium being used in the manufacture of beer.
Mr. VANSITTART was as ready to acquit the Plymouth brewers as those of London (a laugh) of the charge of using this noxious ingredient.
Mr. SHERIDAN thought that as Government had such information as they described, it was not sufficient to levy a tax upon opium ; for that was in fact nothing more than to let the State partake in the profits of poisoning the People. Some measures effectually to punish the manufacturer and prevent the sale of such noxious beverage ought to be immediately adopted.
The CHANCELLOR of the EXCHEQUER explained the cause of the proposed increase of the tax upon opium; while it was not at all too high for the sale of it as a medicine, he confidently hoped it was too high to discourage the use of it in the adulteration of beer. As to any further measures of prevention or punishment, he considered the laws already in existence quite adequate where conviction could be brought home.
After some further remarks by Mr. Sheridan, the Chancellor of the Exchequer, Mr. Hobhouse, and Mr. Vansittart, the motion was agreed to. The House resumed, and the Report was ordered to be received to-morrow. "
Morning Chronicle - Thursday 16 June 1803, page 2.
The accusation of adding opium to beer crops up quite a bit, but I can't ever remember seeing a case where a brewer or publican was prosecuted for it. While there were plenty of convictions for other adulterants. You have to wonder if it's all just a myth.
The same newspaper article recorded another Parliamentary debate. This one on Report of the Committee on the Survey of the Highlands:
"Mr. BASTARD objected to the application of the public money to any other purpose in the present conjuncture, than the defence of the country."
I thought Alan B'Stard didn't enter parliament until the 1980's.