LONDON (Reuters) - Four former executives from News Corp's UK newspaper arm will appear before a powerful parliamentary committee on Tuesday in the ongoing hunt to establish who knew what about phone hacking and whether James Murdoch did enough to uncover the scandal.

The committee called the four men who no longer work for News International -- two lawyers, the head of human resources and an editor -- after evidence emerged which suggested that the company had engaged in a huge corporate cover up.

The four will appear before the Culture, Media and Sport Committee to answer questions on their role in the hacking affair, which wiped billions off Rupert Murdoch's company in July as a sense of crisis engulfed the firm.

Their testimony is likely to increase pressure on James Murdoch as two of the men have already contradicted Rupert's son over what he knew and when, while another has accused both Murdochs of "serious inaccuracies."