The article is about the number of overseas workers, working in the UK. It uses statistics from the Office of National Statistics. The ONS is a an independent producer of official statistics in the UK. This makes it a reliable source of data.
The Daily Mirror claims that 11% or an estimated 34 million workers. After looking at the original statistics from the ONS claims that out of the total work force, 7% were from the EU and 3.9% were non EU nationals. The Daily Mirror reported these figures accurately. These numbers are from the total workforce, The Daily Mirror reported that EU immigrants make up 10% of the work force in some sectors. In the wholesale sector 14% of the workforce is from the EU, this was accurately reported by the Daily Mirror. Around 17% works in the communication sector. This makes the headline representative as in both those sectors EU workers make up more 10% of the work force. Overall, the Daily Mirror has reported the figures taken from the ONS accurately.