Poor English and mathematics skills have cost around 1.4 million Brits the chance to earn a promotion, according to a new survey.
More than six in ten manual sector workers also admitted in the Learndirect poll that their deficiencies in these basic areas meant that they were losing their employers' money. Four in ten members of the retail workforce are also letting down their bosses with poor skills.
"The research confirms that the current lack of basic skills is having a damaging effect on businesses across the UK," observed Michelle Lofthouse, director of corporate development at Learndirect Business.
"A good understanding of basic maths and English is essential for employees to be effective in their roles and for businesses to achieve success," she added.
A lack of straightforward skills costs employees as much as £823 million each year, as they are short-changed, misled or ripped off, the research also found.
"Recent studies have shown there are 26 million adults across the UK who have a maths or English need," said Learndirect's Sally Coady.
"However, many of these people may not realise their basic skills are holding them back."