Fatal Error after 2.8 upgrade

I tried through the dashboard upgrade automatically to version 2.8 from 2.7..1 and it didn’t complete now when I try log into my dashboard I get

Fatal error: Call to undefined function esc_url() in /usr/local/psa/home/vhosts/chirocentre.co.uk/httpdocs/wp-admin/includes/dashboard.php on line 123

What can i do to fix this without losing my info?