Photo credit: Worcester City Museums
Darkened varnish makes it difficult to discern the status of this portrait but the model is definitely after Lely. There are at least four other versions on Art UK.
Studio of Peter Lely, ‘Prince Rupert, Count Palatine’, c.1670 (National Portrait Gallery, London) https://bit.ly/2QdL8Af
Peter Lely, ‘Prince Rupert of the Rhine (1616–1682)’ (National Trust, Hartwell House) https://bit.ly/2TxjBsw
Peter Lely, ‘Prince Rupert (1619–1682), 1st Duke of Cumberland and Count Palatine of the Rhine’, c.1665 (National Maritime Museum) https://bit.ly/2OVsmsE
After Peter Lely, ‘Prince Rupert of the Rhine (1619–1682), KG, in Garter Robes’, before 1684 (National Trust, Chirk Castle) https://bit.ly/2R0epvu
Art UK adds:
Peter Harrison enquired about this painting on 18 September 2018: ‘Is this the original to Sir Peter Lely's known studio copies of the same composition, of which there are examples in the National Portrait Gallery and within a private collection?’
The collection comments: ‘The crest in the top left corner means that it is part of the Bowles Collection which came to Worcester in 1850 and is mostly portraits. On the reverse these paintings originally had a pasted slip saying, ‘Presented to the Worcestershire Natural History Society through their President Sir Charles Hastings (illegible) by George Downing Bowles, clerk m. a. (illegible) of the Shrubbery, Great Malvern, Oct. 1st 1850’.
This is not my family line, but I have details of Rev. George Downing Bowles (d 1863), who descends from Charles Bowles of Chatham, High Sheriff of Kent in 1658. He donated 26 "fine old oil paintings" to the museum in 1850. The right hand arms are those of his mother Anne, daughter of Rev. James Stillingfleet, Presbyter of Worcester. The left hand arms are Bowles, quartered with Draper. The crest is Bowles, the motto I don't recognise. The Stillingfleets would be my first line of investigation into provenance, as they had a long connection with Worcester. I hope this is helpful.
Sorry, Anne Stillingfleet was his wife.
This is one for Catherine Macleod and/or Diana Dethloff as current cataloguers of Lely; but, unless its status is immediately clear, its an interesting case of how Art UK might advance from an 'unknown artist' description when it clearly is broadly 'Lely' but hard to be sure if by him, from his studio, or just 'after'
I emailed Catharine McLeod and Diana Dethloff about 2 weeks ago. If we don't hear anything this week, I'll try them again before Christmas.
I’m sure the coat of arms in the upper corner is a later addition and may well have been painted upon aquasition much later. Although the photo is some what difficult to tell there definitely appear to be some passages within this work that ring true to Lely himself.
Peter, as mentioned in the intro, the coat-of-arms relates to the painting being formerly part of the Bowles Collection - you will find several others in the Worcester Collection with the same arms. They are those of the Rev George Downing Bowles (1791-1863), impaling those of his wife Ann Stillingfleet - it was he who donated paintings from the collection to Worcestershire Natural History Society in 1850, whence they later passed to Worcester City Museums.
Bowles and Stillingfleet were married in 1818; so yes, the arms were clearly added to the portrait later as a sort of ownership mark - a rather misguided choice of one, it has to be said.
There seem to be 2 more portraits of Prince Rupert Prince Rupert worth of consideration for "Peter Lely or studio?".
One is at Philip Mould, ascribed to "Studio".
http://philipmould.com/browse-art/old-masters/16th-17th-century/prince-rupert-lely-studio. In his entry Philip Mould states - "It appears that Rupert only sat to the great seventeenth-century court painter Sir Peter Lely once and the ad vivum head study was then used as the basis for a number of compositions by Lely and his talented studio assistants."
Another one (with a slightly different pose) is at YCBA in CT, USA - https://collections.britishart.yale.edu/vufind/Record/1667617, where it is also considered as "Studio".
In Frederick Duleep Singh’s “PORTRAITS IN NORFOLK HOUSES“ book (referring to 1904 Christie's sale of portraits from Raynham Hall, Norfolk) I've found a description which matches this portrait - "PRINCE RUPERT. Lot 18. Standing to the left in armour, with long red sash, holding a baton in his right hand and pointing to a camp in the distance. Size 49 by 41 Purchased by Viscount Cohen, £105."
I took a liberty to put together a table of PRINCE RUPERT portraits
discussed above for clarification.
Dimensions, cm Year Collection
1 121 x 95 Worcester City Museums
2 105.4 x 80 1670 NPG, London
3 125.5 x 100.5 NT, Hartwell House
4 123 x 99 1665 Natl Maritime Museum
5 125.5 x 103 Before 1684 NT, Chirk Castle
6 123 x 100.5 Private Coll., UK/Mould
7 125.7 x 101 1666 to 1671 YCBA
Any response from Marion Richards enquiry to "Catherine McLeod and Diana Dethloff"?
Barry, thank you for your comments, including the list of portraits. I had no reply to my email to Catharine McLeod and Diana Dethloff. I'll try again.
The face might be by Lely, but not the rest, and that would be in keeping with his known practice.
Quite possibly, there was never an entirely autograph version of this portrait, unless it has not survived or is untraced.
Having seen this painting at close quarters today at the Worcester Art Gallery I can confirm that the painting is extremely well executed.
The face in particular is very impressive. A beautiful portrait fitting that it is in Worcester with its important civil war connections
The precise status of this item is not going to be resolved until the current Lely cataloguers get round to it, which their non-response so far to requests for a view suggests is not yet. The interim Art UK and collection resolution should probably be to call it 'Sir Peter Lely' or 'Sir Peter Lely (studio)' for more exact definition later, not just leave it as 'Unknown artist' - which it certainly isn't - and as a pointlessly open-ended discussion here for what may be a period of years. That at least puts Lely into the system as a related search term. Even in what looks like a pretty darkened state it looks probably a studio version of a familiar type, rather than a later copy, (50 x 40 in. +/-, in Garter robes against a columned background) of which Art UK alone lists another three excluding that explicitly 'after' at Chirk Castle (NT). They are probably all at least 'and studio' irrespective of how currently described, as one would expect. Worcester would do well to get theirs cleaned since it would probably come up splendidly: e.g. like this one, which Rupert gave to his secretary, Colonel Bennett:
Moustache- curious- the RMG version ( just above) does not seem to have a moustache ?????
Rupert's moustache often tends to be more five-o'clock shadow: this is a better image of the Greenwich version
...and one by Samuel Cooper:
There are seven known copies of Rupert from the studio of the Peter Lely in stock Knights Garter robes . All based on RCIN 405883. The HBC corporate office in Brampton, ON is keeper of one of these copies. The example in the HBC Museum Gallery, Winnipeg is a poor copy  based on the Brampton copy. Attached photo, credit: Lauren Bosc