Reader RG was surprised to see this in a BBC News item ("Violin world record broken in Taiwan", 9/18/2011):
A group of 4,645 violinists broke the world record for the most number of violins played simultaneously.
This sense of (the) most is presumably the superlative of many, and thus "the most number of violins" means the same thing as "the most violins". One motivation for adding the "number of" part may be that (the) most is also the superlative of much — in that case people sometimes specify "the most amount of". Thus another BBC News item, "Matthew Arnold pupils get chocolate for energy saving", 6/15/2011:
Matthew Arnold School was rewarded for saving the most amount of energy on Oxfordshire's School Switch Off day.
These uses don't seem to be covered in the OED's entry for most, but there are a couple of examples of "the most number" in quotes for other words:
2003 Western Daily Press (Bristol) (Nexis) 21 July 21 Hundreds of the giant pepperpot-like robots are descending on Wiltshire's Longleat estate in a bid to create a record for the most number of Daleks gathered in one place.
1572 Treat. Treasons against Q. Elizabeth ii. f. 169, Speaking seuerally of the most number of them, whose iudgements are regardable.
Both idioms are fairly rare — there 19 examples of "the most number of" in the COCA corpus, and 30 examples of "the most amount of", for rates of 4 per 100 million and 7 per 100 million respectively. The BNC (in 100 million words) has 4 instances of "the most number of" and 2 instances of "the most amount of"
But these expressions are certainly Out There in the media, at what seem to be higher rates than these. Thus a current Google News search for "the most number of" returns 349 items dated within the past three weeks or so. If the rate is really 4 per 100 million words, this would imply that Google News is indexing about 9 billion words of current English-language news, which seems a little high to me.
Curiously, many of the hits from this search are Asian — from the Philippines, Australia, Malaysia, Sri Lanka, etc.:
PHL one of 15 nations with most number of Miss Universe Awards [headline]
A Filipino organisation from the St. Mary’s Catholic Church in Dubai, garnered the most number of votes in the Filipino Community in Dubai and the Northern Emirates-Governing Council (Filcom-DNEGC) elections held on Friday afternoon at the new location of the Philippine Consulate General (PCG) on Beirut Street, Al Qusais.
Universiti Malaysia Perlis (UniMAP) won the most number of gold medals at the three-day 2011 International Conference and Exposition on Inventions by Institutions of Higher Learning (Pecipta 2011) which ended Thursday.
Five Australians have made it to the Tour Championship in Atlanta representing a significant percentage of the 30 man field that will line up at East Lake Golf Club next week. It is the most number of Australians to have made it to the Tour Championship in the history of the event.
ICBT Campus the leading private sector Education Institute in Sri Lanka was awarded by Edexcel, UK as Sri Lanka's largest center with most number of students enrolled for Higher National Diploma (HND) programmes.
Basilica College, Ragama is one of the youngest schools in the country to have made a prominent name in the sports arena especially at cricket. As at today, Basilica is an upper school with classes for students of above the sixth grade and has 1525 students in both genders. It is the most popular school in the Ja-Ela division with the most number of students in attendance.
The organization has ranked the Philippines second among participating countries with the most number of volunteers.
"Possibly a new Australian record for metropolitan racing was established on Saturday, September 3, for the most number of runners on one day bred in the northern hemisphere competing," Brian Russell reported on his Racing And Breeding News.
But there are also things like this — Allison Jones, "Social media a powerful election tool but no match for door knocking: experts", The Globe and Mail 9/18/2011:
“The only reason we're doing any of this at the end of the day is not to have the most number of friends, most number of followers, any of that kind of stuff,” said Joseph Lavoie, the director of social media for the Progressive Conservative campaign.
“It's actually to get out the vote, because none of this is worth it if we don't win on election day.”
And this — "Local gymnasts working toward breaking handstand record", Corvallis Gazette Times, 9/16/2011:
Corvallis’ PEAK Elite gymnastic center is participating in a national event on Saturday to break a world record for the most number of handstands performed at the same time – and local residents are invited to join in the effort.
And a Google News search for "the most amount of" doesn't deliver the same Asian flavor.
These idioms have been around for a while, as indicated by a well-known passage in the Book of Common Prayer, here reproduced from a 1637 edition:
This probably reflects the fact that most was (is?) also the superlative of great.
The earliest examples that I've been able to find for "the most amount of" are instances from 1840. One is this lovely specimen of praeteritio from The Church of England Quarterly Review:
We say nothing of all this additional duty being expected to be done without remuneration, as it is pretty well known now, in spite of the ravings of interested demagogues and scribblers of sedition, that the clergy are the men, taking them generally, who do by the most amount of work for the least pay, and who are always the readiest to meet the heavy demands, whether for time or money, or grautitous labour, which are continually being made upon them.
The other 1840 instance is in a report on the Liberia Mission of the M.E. Church:
Bushrod Island.–We have no society here, but the word of God is preached to the few persons who can attend. The most amount of good is done to the poor sufferers at the almshouse. The poor "have the Gospel preached unto them," and it is not unfrequently made the power of God to their salvation in the dying hour.
Expressions like "the most amount/number of" are a natural target for the "omit needless words" squad: thus "the most number of violins" means essentially the same thing as "the most violins", and "the most amount of energy" means essentially the same thing as "the most energy". And the superlative use of most usually associates with plurals as the superlative of many ("the most votes") or with non-count nouns as the superlative of much ("the most money") — but both number and amount are problematic by this criterion, since they're singular count nouns. You could save this generalization by substituting expressions like "the largest number of violins" or "the greatest amount of energy".
Nevertheless, I'm not aware of any campaigns against "the most number of" or "the most amount of"; and neither string occurs in Merriam-Webster's Dictionary of English Usage.
(Please understand that I'm not lobbying to start such a campaign. I have nothing against well-established idioms like "the most number of" and "the most amount of", whose redundancy may serve to increase clarity. I'm just puzzled by the apparently failure of the Usual Suspects to defend the purity of the English language against the assault of illogical and word-wasting barbarians — with the first of the barbarians in this case being the Book of Common Prayer.)