As you know, I have an interest in William Whewell. I was reading Whewell's sermon, Strength in Trouble, which was published in 1851 (I do not know exactly when it was originally delivered). The sermon is partially a stern warning and partially an earnest exhortation for people to stay Anglican. Since we're talking about Whewell, he's subtle enough that it's hard to catch details, but clear enough that there's no question what 'Egypt' represents in the sermon. My first thought was that it might be anti-Tractarian, or even have Newman in view; which would be interesting, but is probably wrong. Todhunter says that the sermon is concerned with the Gorham controversy, which is extremely likely given the date of publication -- the Gorham controversy led to a fair number of Anglicans converting to Catholicism after a secular court -- the Privy Council -- ruled that the High Church bishop of Exeter was wrong to have refused to institute a Calvinist Evangelical (Gorham) to a vicarage (the specific ground was that Gorham denied baptismal regeneration). The conversions were due to the shock of finding that so many Anglicans held, or seemed to hold, that the teaching authority of the Church of England was from the state. Manning is probably the most famous convert in the wake of the controversy. The controversy had been aggravated by Wiseman preaching a vivid sermon on the controversy (in which it is a storm rocking the ship of the Church of England, which therefore desperately needs to return to the Catholic Church), which elicited some rather heated replies, like this one. Whately also got involved, with an attack on the High Church view of baptism. Many of the other big names of the time got involved in one way or another (although I know of no comments by Newman on the subject).
Project Canterbury has a page devoted to the controversy.
In the comments Miriam notes that Newman discusses the controversy here.