Each time I create a new page, instead of loading the new page, the CMS presents me with a blank screen. The blue panel (pages, files, reports…) is still of the left hand side of the screen, but the rest of the screen is just grey. The new page is created however, I have to hit refresh to see it listed.

Is this normal?

Sounds like you have an error in your code, try setting the site to 'dev' mode, and see what error you're presented with. http://doc.silverstripe.org/en/developer_guides/debugging/environment_types/

I'm in DEV mode.

There's no error message on screen. Just blank.

Nothing in the JS console either.

Pastebin the code for your page maybe? I'll have a look.

The problem is not particular to one page, it happens whatever the new page is I try to create.

Could be the Page.php if you've edited that. Have you done a dev/build and a ?flush?

Yep dev/build and ?flushed several times. This is my Page.php:

<?php
class Page extends SiteTree {

	private static $db = array(
	);

	private static $has_one = array(
	);

}
class Page_Controller extends ContentController {

	/**
	 * An array of actions that can be accessed via a request. Each array element should be an action name, and the
	 * permissions or conditions required to allow the user to access it.
	 *
	 * <code>
	 * array (
	 *     'action', // anyone can access this action
	 *     'action' => true, // same as above
	 *     'action' => 'ADMIN', // you must have ADMIN permissions to access this action
	 *     'action' => '->checkAction' // you can only access this action if $this->checkAction() returns true
	 * );
	 * </code>
	 *
	 * @var array
	 */
	private static $allowed_actions = array (
	);

	public function init() {
		parent::init();
		Requirements::css("http://fonts.googleapis.com/css?family=Open+Sans:400,300");
		Requirements::css("http://maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css");
		Requirements::css("{$this->ThemeDir()}/css/bootstrap.min.css");
		Requirements::css("{$this->ThemeDir()}/css/theme.css");

		Requirements::javascript("https://code.jquery.com/jquery-1.11.2.min.js");
		Requirements::javascript("http://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js");
		Requirements::javascript("{$this->ThemeDir()}/javascript/jquery.mobile.custom.min.js");
		Requirements::javascript("{$this->ThemeDir()}/javascript/jquery.lazy.min.js");
	}

}

Page class seems to be OK, can you check the response e.g. in firebugs network tab? Or even better: set up error logging and watch the logs, both, your silverstripe logs and the webserver error log.

Could also be an extension that is plugged to SiteTree or Page that is causing trouble, or if the page wants to create a directory in assets but doesn't have write permissions, etc...

If you still don't see any error it might be suppressed (grep for the @ sign before a function call... error suppression is a very bad practice!) or some kind of php error (which would be logged in webserver log or syslog)

In any case: good luck!