posts_per_page not returning expected result

Hi guys,

For the life of me I can’t see why posts_per_page is still only returning 5 posts even though I have set it to -1 to catch all posts within that category. There are over 60 of them!

Any help will be appreciated.

<?php
$args = array( 'posts_per_page' => -1, 'offset'=> 0, 'category' => 6 );
$lastposts = get_posts( $args );

foreach ( $lastposts as $post ){
  setup_postdata( $post ); ?>
	<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>

<?php }

?>