The Catholic general secretary of the Trades Union Congress (TUC), Frances O'Grady, will today deliver a speech at the Vatican arguing the 'titans of technology' such as Apple and Amazon are depriving working people of dignity.

The speech comes during a two-day meeting of Catholic and labour movement leaders which will hear of injustices suffered by working people, consider the structural reforms needed to the global economy to put human dignity before markets and capital, and serve as a chance for trade unions and the Catholic Church to share ideas in order to achieve greater social justice for working people and their families.

O'Grady, who came 8^th in a recent list of influential Catholics by the respected journal The Tablet, will warn of the harm done to UK workers by inequality and corporate power, including tax avoidance by new 'titans of technology' like Apple, Facebook and Google, and worker exploitation by firms like Uber and Amazon.

Catholic teaching through papal encyclicals has commended trade unions, highlighting their importance as what the late Pope John Paul II called 'a mouthpiece for the struggle for social justice, for the just rights of working people'. O'Grady will call on the Catholic Church and trade unions to continue their historic association by building an alliance for economic justice.

She will say: 'The Catholic Church and trade unions have a shared history in Britain. In the 19th Century, Cardinal Manning supported striking dockers who demanded a pay rise, minimum hours and the right to a union voice. He called the refusal of employers to negotiate with their workers a "public evil".

'This year I met the "McStrikers" – young fast food workers at McDonald's, stuck on low pay and zero-hours contracts. Their demands are the same as the dockers nearly 130 years ago. They want a fair wage, guaranteed hours and recognition of their trade union. They need a modern-day Cardinal Manning.'

She will address global challenges that permeate inequality, saying: 'Inequality, conflict and climate change are threatening the peace and prosperity of the world. Technological change is concentrating wealth at the expense of working people. And our schools and hospitals suffer from rich corporations not paying a fair share of taxes.

'New global titans of technology now have wealth and power beyond our imagination. And many workers have become slaves to an app, with employers washing their hands of any notion of an employment relationship. We must offer hope that there is a better way.

'We must challenge the very values on which our economies run. The market should be our servant, not our master. Value cannot be measured in monetary terms alone. And individual greed must not triumph over the common good.'

She will ask Catholic leaders to work with trade unions, which, she argues, have much in common, saying: 'The Catholic Church and trade unions both understand that much more can be achieved together than alone. We share values of community, dignity and social solidarity, values that bind us together as workers, citizens and human beings.

'Together, we can improve working lives and put dignity for working people ahead of market forces and freedom of capital. We can build a popular alliance for economic justice, in Britain and around the world.

'So speak out and support the courageous workers who stand up against injustice. Call on your congregation to join a union. And encourage Catholic employers to do the right thing and recognise trade unions.'