Struggling England batsman Kevin Pietersen admits his confidence has been "hammered in the last 18 months".
The 30-year-old has appeared short of form against both Bangladesh and Pakistan so far this summer and has not scored a Test century since England visited the West Indies in the spring of 2009.
That tour came just weeks after his departure as England captain in the wake of a falling out with then coach Peter Moores and, according to Pietersen, the acrimony surrounding that bust up is at the root of his malaise rather than any technical flaws.
Speaking prior to the fourth Test against Pakistan at Lord's, which got underway on Thursday, he told Sky Sports 1: "I'm not one of those guys who likes to say I'm playing well in the nets. Talk is cheap, but I'm trying so, so hard to break this barren run of hundreds.
"It does concern me. I'm always looking to try and improve. I've got to look at the positives and drag my confidence up, which has been hammered in the last 18 months.
"I'm nowhere near the person I used to be but I've got to keep trying to work at it.
"I've got a hell of a lot of starts and a hell of a lot of 80s and 90s. I was thinking if I'd converted those I'd have four hundreds in the Test year which is what I usually get.
"It's purely down to confidence and purely down to what's happened over the last 18 months. I'm trying so hard every day to get back to where I used to be.
"I'll get there."