Seattle increased the minimum wage from $9.47 to $11 an hour and then from $11 to $13 an hour. In the $9.47 to $11 an hour increase income outweighed employment losses to produce an average increase in earnings (about $24 a month). The $11 to $13 increase produced the opposite effect. It not only decreased average earnings ($125 a month), but it did so enough to wipe out the increase from $9.47 to $11.
How does this compare to the Labour proposal? £10 is roughly $13 and £7.50 is roughly $9.74 under the current exchange rate. If the United Kingdom is similar to Seattle (in the United States), the proposed increase would reduce average earnings because hours would drop more than hourly wages would increase.
It's worth noting that Seattle is in a relatively high wage area of the US. While there are a couple other cities that might do better, like New York City and San Francisco, many regions would not. For example, $15 is higher than the median wage in most of the South. That said, the UK is a different country, and wages are more likely to be comparable to Seattle there than in the rural South US.
Note that even the $9.47 to $11 increase caused hours to drop. It just caused the hourly wage to increase enough to offset that on average. That's fine for those whose pay goes up. It's kind of hard on those whose hours are cut or worse, eliminated. This is important, because people who lose their jobs entirely can't get better jobs. They have to sit around and wait for an opening in the same lousy jobs from which they were laid off.
The problem is of course that the first people laid off tend to be those with the least experience. I.e. the ones who have the most trouble finding new jobs. The UK's separate rules for those under 25 may help with that, but in the US, the places with the highest minimum wage also tend to have the highest youth unemployment.
It's noteworthy that Denmark has high wages, a robust safety net, and no statutory minimum wage. Its "minimum wage" is set on an industry by industry basis through agreements between employers and unions. Sweden, Norway, and Finland operate similarly.
And these are the short term effects. Longer term it's possible that labor might be replaced with automation, even at the $11 level. And of course, the money has to come from somewhere. Short term that might be ownership. Longer term, it is likely to come in the form of higher prices. As a general rule, owners have more investment options than consumers have purchase options.