I dont believe I am looking at this through O&G tinted glasses though. I feel its irrelevant in this instance.
The Cambridge definition does not exclude a £60k wage as a working class one as far as I can tell.
1, belonging to a social group that consists of people who earn less than other groups, -£60k is still less than other groups though, for example O&G, Banking, Insurance, NHS Diversity and Inclusion Officers.
2, often being paid only for the hours or days that they work, and who usually do physical work rather than work for which you need an advanced education”- As Eggs mentioned, there is plenty out there on £200-£300 a day who are paid for physical labour and the hours that they work. £250 a day for 24 days a month and 12 months a year is £72,000 a year. Taking some holidays and you'll still be over £60k a year. My own Brother who is in the building trade and basically does odd-jobbing these days has made over £75k so far this year.
£60k is not a great wage in the traditional nuclear family setting is it? With a single income from either spouse, you'll live an ok working class lifestyle off of that. You'll not be able to afford to buy much of a house on that wage. You certainly will not be able to afford more than one average holiday a year. You not afford any of the indicators that mark a family as middle class thats for sure. Even if both partners earn £60k a year you might find yourself on the bottom rung of middle class but I dont you'll be taking two exotic holidays a year, have two new vehicles, have a large detached house with grounds, or send your children to private school.
People have gotten far to used to living on £120 a day and thinking thats a good wage. Thats laborer money. Even my 19 year old is getting over £10 an hour working at KFC ffs. Now thats a working class job.